Under $600 will have to be 4K. Don't let the spin about 5K overwhelm you. Mac looks quite nice on 4K screens at that size... just a little better on 5K screens at smaller than target size. Many of us will work hard to convince each other to buy 5K and only 5K... and once someone takes that bait, then ONLY Apple 5K is good 5K.
If you want to test this, hook his new Mac to a 4K TV to get a peek at how macOS will look on a 4K panel. You'll find it looks pretty good. Now imagine how much better it will look when that same number of pixels are compressed down to a 32" space vs. whatever size 4K TV you/he may already own now. OR, take the Mac to a monitor retailer and connect it to some 4K monitors to see first hand what macOS will look like with your
own eyes.
I'm with #2 if $600 is the hard budget. I purchased a Dell monitor when I embraced silicon a few years ago and am delighted with it. The built-in hub is loaded with both "the future" and "the present" ports- no dongles or additional hubs required to just hook existing stuff to it. The one I chose is a 5K2K 40" ultra-wide way over your budget (about the same as ASD with stand option) but I could never come back from all that ultra-wide screen space now that I've enjoyed it for a few years with Mac.
Another worth considering with good ratings is the 32"
M80C from Samsung. A little shopping around and/or watching for the regular Samsung sales will likely get it for $600 or less... though the hub is substantially less loaded than that Dell.
If Apple fans convince you 5K or bust in posts likely to follow, consider the brand new
ASUS 5K monitor for only $799 new. Note however that it shrinks your target screen size down to only 27"... just like ASD. To buy Apple and only Apple at your screen size target, there's only one and its
monitor stand alone greatly exceeds your budget target.
One last thing: monitor speakers- like TV speakers- are usually a poor quality option, though give some points to ASD here as those sound pretty good. Perhaps the NEXT gift after
this purchase would be some quality dedicated speakers OR consider something most people don't and get a good soundbar with wireless sub to deliver great sound for a relatively cheap add-on cost. No built-in speakers can compete with such a sub for low bass and a soundbar is built to deliver high quality sound in a very competitive environment (often overkill for computer audio purposes). The added hardware space allows quality of sound to be greater than speakers crammed into a "thinner" space.
Regular speakers with sub might be something like the very well-rated Logitec Z407 for about $100 or the Klipsch ProMedia 2.1 for about the same. A low cost soundbar with wireless sub might be one of the Vizio 2.1 soundbars for about $175 or maybe the LGS70TY for about $250. Shop hard for any such options as all such speakers operate in a very competitive space and pricing is always under pressure to work its way DOWN.
