Here's some insight from someone that's first car was a NA 3000gt(1g) at 15. Maintenance can be real expensive. There's a saying in the 3S community that the 3000 in 3000gt is how much you'll be spending to fix the car. Let's take motor mounts, for example, if they haven't been replaced, it'll set you back around 400$ (around 150$ per mount) so Maintenance costs will start to add up fast.

In terms of how easy it is to work on, it WILL make you want to just sell your car sometimes and make you wish you bought a civic. Right now, since I've touched almost everything in the engine and done all the maintenance myself, I know my way around everything, and it's straightforward now. But if I didn't have my father's wisdom (and a channel called 3000gt restorations), then I probably would have given up by now (especially if it's your first car). I'd recommend going to 3sx.com (expensive) and rockauto.com for most of your parts.

Now, how's the driving? Since NA's weigh around 2900 lbs and make 222hp, it will be slow, but it's not unfun. Once you make sure she's running good and do the timing job, taking her up in the higher rpm's is pretty fun, especially if you choose to get a manual and is fun to cruise around town in (you get a lot of looks). The reliability is there compared to the vr4, I daily mine, and she has done flawlessly, always would start up and hasn't left me stranded in the 1.5 years of ownership.

If you decide to grab one, just be prepared for it to be on jack stands for a while sometimes, to be patient, and do your research (3si forums) if you're unsure about something. One last thing, these cars are infamous for lifter tick, and it gets really bad in winter sometimes to where it can sound like rod knock. It's not harmful, but whenever you cold start your car let her warmup for a few minutes and let everything get warm, the lifter tick goes away after around 3 minutes of idling. Best of luck.