Personally, I liked my YJ better than my XJ, but that being said....if you're trying to talk her out of it, just understand that it will never be "dry, warm and quiet as possible". If she can't deal with that, major selling point! Another one is security...the SWB Jeeps are stolen much more frequently. She also has to understand that anything she keeps in a soft top Jeep WILL be stolen. You can get her a hard top, but seriously, what's the point? The only reason to have a wrangler is for the easily convertible nature of it. Put a hard top on it and you have to have a hoist/friends and place to store giant POS if you do want to go topless...not to mention, there's no way of deciding to "drop the top" when the day goes from cold and grey to warm and sunny.
Not to mention, if she wants a nice stereo...wrong car! (Again, take into account, I'm of the opinion that if you want a wranger...you want a soft top wrangler....the only time you get a hard top for your wrangler is if you want both) If she stores stuff in her car when she's at class/work...wrong car! A sharp blade or a theif bright enough to undo a snap can get into this car. You can put alarms on 'em...you can put extra locks on 'em....you can put The Club on 'em....won't help, they get broken into and and swiped more than most cars because of ease and simplicity of design.
As for the ride...it's rough. The vehicle spring design argues against physics and causes it to be bouncy, PERIOD! You can get a shackle reversal to eliminate most of the bounce, but then you have brake dive to deal with...for a novice driver, it's scary as hell! =)
However, a wrangler is what most people think of when they think of a "Jeep". There is something about a topless, doorless Jeep that just stands out from any other, i.e., XJ, MJ, WJ, ZJ, KJ, etc. Of course, take in to mind, If I said "CJ, TJ, YJ" to an average Joe, most would have no idea of the difference. But the basic design of the short wheelbase jeep hasn't changed for almost 50 years, from the first willy's to the TJ. When people think of a Jeep, that's just what they think of....and generally want.
Offroad, I think they perform far superior to my XJ. They are cheaper to modify...lifts are nearly half the cost. Parts are more readily available...several aftermarket dealers sell body parts, even the entire tub. More aftermarket parts are available in general...and cheaper than the corresponding piece for the XJ...not to mention a much greater variety than what you can even find for the XJ. Now a TJ, the lifts are a little more expensive, around the cost of a lift for the XJ, but the aftermarket parts (bumpers, tops, doors, seats, speaker boxes, engine mounts, friggin' anything) are still much more readily available.
Regarding the doors, I'd say give her half doors. We live in Southern California, so there is a good bet that most the time is going to be spent with the top down and perhaps a bikini top on. Full doors on a topless jeep are just gay IMHO. And if you're thinking strength, you have to understand, no door on a wrangler is ever safe. Most of it is plastic....even in a full door. It's more for heat retention than anything else....something you don't deal with here...but if you have a Jeep with full canvas doors in Denver, you know what I'm talking about. =D At least with the half door, you don't have the threat of glass being thrown around. Or, go with the best of both worlds and get her both. If it's a YJ, there are not "inserts" for the doors to seal, so she can readily change from no door to half door to full door at will. If it's a TJ, there are plastic guards that go in place for the doors to seal, so it's a bit more of a hassle. But even at that, at least she can still have that ability.
As for being dry, the only time mine leaked was during a heavy downpour, and then the water came in from under the top bracket that mounted to the winshield. To solve it, I took it off, coated it with RTV, screwed it back on....no more leaks....oh, other than the water that drips out of the vents when it rains. This you can't help, it just happens...deal with it. The fresh air intake vent is horizontal, so when it rains, water comes in. It's just a fact of owning one. Get used to it. Fortunately, it rarely rains in sunny CA, so not much of an issue...one, maybe two, days a month it rains hard enough for her to experience it. And even then its just a periodic drip that falls on your left knee.
As for quiet, well, again, not something you can really do much about. You can herculine the tub and put some thicker carpeting in. That will help heaps....not to mention, it will help keep the heat out as well.
Ok, that was probably more than you wanted, but I'm on my 4th Cap'n and coke, so deal with it. =)
P.S. Regarding the 89-90, they also had the Peugot tranny....major bummer if it ever has problems!....think it was in the '91 as well. I always look for a '92-95 myself....but I'm a sucker for the rough ride of a leaf sprung jeep. =)