I know Gibson uses a nitrocellulose clear coat, so it actually helps the aging process of the wood and prevents paint fade and cracking, but PRS doesn't use that process, does the finish hold up regardless?
Actually, that's incomplete information, and some of it is urban myth.
PRS uses mostly nitro on its Private Stocks unless a customer requests otherwise. It has done so for a long time. Unlike Gibson's formulation, the PRS nitro used on their PS guitars doesn't tend to get sticky. Nitro is a far more delicate finish than what PRS uses on its production guitars, called V12, which as I understand it is kind of a blend of nitro resins and poly type binder.
Though I've owned PRS since 1991, and I should be drawn and quartered for not keeping them longer, in 1999 I bought my son a CU22 Soapbar that he played until two years ago, and toured with. I bought it back from him, and the guitar still looked near-new in 2012. That's pretty typical for a PRS in terms of how it holds up. So, thirteen years, daily use, looked new, and my son doesn't baby his instruments. Oh, and we bought it second-hand, the guitar was a 1998.
The urban myth is that nitro somehow enhances the process of the guitar's aging.
Nitro often begins to crack and check as a guitar ages, and it has been theorized that this somehow helps the wood age, but frankly that's apologia and nonsense. PRS ages its woods and then puts them in a slow kiln, and takes the water out of them before the guitars are built and finished, about the only thing a cracked finish might change is that the wood might rot faster. But in terms of tone...no.
I have a vintage '65 Gibson that was of course finished in nitro, and it's cracked all over the place. Doesn't sound any different than when my brother first got it in 1965, except I put a tune-o-matic bridge on it in 1970. So there's that one difference.
I'm absolutely 100% sure the choice of nitro or poly or some blend like V12 doesn't prevent paint fade and cracking. It can't without some kind of UV additive.
In fact, nitro is far more susceptible to cracking and checking than other, more modern finishes. And colors underneath the clear coat of any guitar, PRS or Gibson are only stains, not paint (unless you're talking about an opaque finish), many of which are equally susceptible to fading in strong light because they use organic dyes (something that can't be helped as inorganic dyes are not as transparent and would hide the features of the wood).
That said, I prefer nitro because it might, maybe, produce a guitar that sounds a little different. I can't prove that, and it certainly wouldn't be due to a cracking finish since my PStocks aren't cracked and are still great though of recent vintage.
I think you'll find that PRSes hold up very well indeed, perhaps better than most new guitars.
What really is important: they start out sounding gorgeous, being finished with great attention to detail, and playability that is second to none. They don't need to be babied. They're fully professional instruments.
In other words, get one and don't worry about it.