I often dismiss discussion about Apple's products being "old" as somewhat alarmist. Yeah, that chip isn't the newest one, but what meaningful improvement would a newer chip bring to the people using that product?
I still think that's true, in most cases, people want a product to be updated but can't point to what the benefit of updating it. Especially the way Apple updates things, where a machine will get thinner and lose ports or have, at best, even battery life. Or, Apple's implementation of a set of chips will result in something that benchmarks lower than the equivalent PC machines using that hardware.
However, I'm pretty much here for the idea that we should frame this circumstance with the fact Apple has a trillion dollars now and should have the money to drop a new processor into its computers from time to time. They don't always have to be first, and I know some of the machines have a reason for being where they are, but I still think it's shameful anyway.
With that in mind, it's very difficult to recommend almost anything in Apple's lineup today, for the simple reason that almost all of it is older than what you'd get from a PC vendor for the same money, and because some of Apple's products today are so old, it's tough to tell what will look bad next time Apple axes off support for old machines. Earlier this summer, the new system requirements for Mac OS X 10.14 "Mojave" were announced and they cut deep: Anything with a Sandy Bridge Intel Core 2nd Gen or earlier is no longer supported, with the exception of a single machine: The 2010 Mac Pro (5,1) with an upgraded graphics card. The cut was made because of support for certain features that the GPU in the 3rd generation CPUs has. This is why the Mac Pro can skip the axe with an upgraded graphics card installed.
The main reason the cut feels deep is that in the Mac scene for the past few years, a common argument is an SSD and a RAM upgrade makes any older machine feel new again. This isn't wrong: My own Mac is a Mac mini from 2011 into which I put some more RAM and an SSD and it has been a sprightly performer since. However, it'll be cut off by 10.14 and it was starting to show its age and some of its other limitations anyway.
Unfortunately, because they're all so old and/or so expensive, there are no new Macs I want to buy. I would extend this to saying I wouldn't really recommend most current Macs without reservation.
In their laptop family, they're using CPU age and capability to tier their various machines into good/better/best slots. If you look at 13" machines, the oldest among them is the 13" MacBook Air, which hasn't been updated since 2014, using a 5th generation CPU. (They speed-bumped it in 2017, but that only barely counts.) Next is the 13" MacBook Pro with no touch bar, where Apple has kept 7th generation processors, and the 13" MacBook Pro with Touch Bar, where Apple upgraded to the new quad-core 15W 8th generation processors.
No other computer OEM is intentionally using old hardware to set price points or justify pricing tiers. Any that are are only using hardware one generation behind, and often that's only because the least expensive CPU models (See: Pentium Gold, Pentium Silver) are themselves at the previous generation. (See: Surface Go.)
Some examples are a little more egregious. Having a laptop with a 7th generation CPU is not bad but keeping a line of desktops at 7th generation for no good reason is a step above. There's no stated reason why Apple hasn't advanced the iMac's platform, but if I had to guess, the reason is that having iMacs at $1,299 with six-core CPUs exist before they discontinue or augment the Mac Pro 6,1, which starts with six processor configurations for $2,999, would look bad. With talk about the 9th generation (and 8-core mainstream CPUs) already floating around, that old Mac Pro looks really bad.
The Mac Pro deserves its own special mention: it launched just under five years ago in December 2013. As of this writing, just a few days ago it officially became the longest sold Mac, replacing the Mac Plus, which sold from January 1986 to October 1990. The Mac Pro was launched to much fanfare with the line "Can't innovate anymore, my ass" which is a little ironic because it launched as an Ivy Bridge EP system on the evening of the Haswell EP launch, and the somewhat unique dual GPU design became outmoded by the launch of bigger, better single GPUs that were better at context-switching between displaying graphics and doing GPGPU work, which was part of the original rationale for having built a system with two small GPUs instead of designing for one or two big GPUs, as most PC workstations at the time did. In addition: density on everything doubled from Westmere to Ivy Bridge, but in response, Apple halved the size and compute capability of the platform, meaning if you tried really hard you could get a pair of Westmere Xeons into the old model that could technically outperform the newer machine. As such, used prices on Mac Pro 5,1 systems have stayed high, even as it becomes obvious the machines are going to be the least well supported by upcoming versions of Mac OS X.
The last system to mention is the Mac mini, which is in the unenviable spot of being slower than its predecessor, less repairable and upgradeable, and un-touched in the product lineup since 2014 when it was announced.
In 2014, I defended the Mini as probably "needing" to be the way it was to be worth building to Apple. Basically, as my speculation goes, the Mac mini is electrically like a MacBook Air or 13" MacBook Pro from its day, and that would be why it got saddled with soldered RAM and no room to install a second SATA device, as the 2011 and 2012 Minis had. In retrospect, that probably wasn't strictly true in 2014, and with the knowledge that Apple has a trillion dollars just sitting around, it feels like excusing the mini for being that much less expensive to design seems like a bad look, so I'm not going to do it. I think that's the explanation, but I don't think it's a good excuse, and it probably wasn't in 2014 either.
The MacBook Pros with touch bar stand out as the only Macs that have been refreshed this year. Those systems should be as good as they always are if you need that kind of system. However, those systems are some of the more expensive machines Apple sells and they are equipped for technical computing, software development, multimedia production, etc.
The MacBook Pro with no touch bar is a good computer, 7th generation is less offensive for something at that product tier (although still annoying as everyone else has updated their midrange machines to 8th gen) than some of Apple's machines still running around with 3rd, 4th, and 5th generation CPUs.
As I said about the MD101LL/A close to the end of its selling life, the MacBook Air would be a good deal at around $600 or 700, Apple would probably still be making a profit on them at that point. The lower price on a machine like that would be a good attraction and a good gimme to the people who were still doing fine on (probably faster) high end machines that got obsoleted out of running 10.14, and it would just look better.
If Apple wants to sell a MacBook Air for $999, it should probably be an updated system.
In a better world, instead of just providing deep discounts on machines it hasn't updated in years, Apple would just update the machines. I can see why it may take a little longer than usual to rev the product line to a new machine. Apple has had a slow time of revamping the Mac Pro, and there have been rumors for a year or two about a new budget model Mac laptop. I remain annoyed that they appear to have used old form factors as a reason not to put any new guts into their machines. I hope I'm wrong about their not updating the iMac for optics reasons, but I'm not overall that optimistic about it.
Back to my buried lede: I can't really recommend almost any machine today. The Touch Bar MacBook Pros are the only machines using current processors and those are high end machines with premium hardware features (the touch bar) for which Apple is charging. It's a good machine if you need that kind of machine. Apple doesn't make a reasonable choice for almost any other kind of machine it sells. You'll almost be better off either buying used hardware, waiting, or going ahead and switching away from Mac, if you can at all get away with it. This could change in the next few days as Apple has one of its fall hardware events, but I believe the immediately coming event is primarily for phones, tablets, and watches.