Unfortunately, NOT many user-serviceable issues on the NS or other GM fwd vehicles!
The side-case seals can be an issue, but in some cases, some shade-tree fixes might work.
Even to chnage the rear valve cover gasket, requires dropping the cradle just to get to it. The hidden starter looks flaky, but we didn't sell many of them, anyway. Even one of our novice techs had one changed in about an hour, and nothing kaputted. Looks scary, as things on many fwd engines do, but not that hard to do. What was worse is changing the $300.00 blower motor!
For dealerships/shops that are set-up to work on these vehicles, things happen as with any other similar GM fwd vehicle.
On the other side of things, as many might not desire to spend the bucks to fix their cars, they get "driven" and sold cheaply. So finding a competent shop that knows about the cars can be important and whom with a lasting relationship can happen. Many of the big expenses will have to only happen ONCE, by observation, as with almost all later-model vehicles.
IF the heads have to be removed after about 150K, it's common for thread repairs to be needed. Sounds flaky, but there have been "Time Zerts" (think Heli-Coil kits) around for years to address this. Just a part of the beast.
"Junk" can be subjective, just depends upon on one's orientations for things they might not fully understand. For some, the Lincolns might be a better fit, but they can have some issues, too! Like the rear air bags!
Either way, keep a reserve of money for future repairs, regardless of the brand. Pay attention to the soft trim items and siuch, too. Get the best one you can find, but don't buy the FIRST one, either. Look around for a while before purchasing! Just make sure that even after spending a $1k or so in repairs,, you can still bail out later without much financial distress. If possible, look for maintenance records on CarFax or similar (a small fee might be needed), for good measure.
Just some thoughts and experiences,
CBODY67