It is my first 'big bike' which I have bought after getting my license last year. I did the driving course on a Yamaha FZ600N (2008 I think) and my girl has a GPZ500, so I can only compare it with those bikes.
I bought this model because there were a lot for sale with few miles on them for very little. I settled on a 1993 black-blue US model, which had only run 6500 miles and was advertised as only needing new tires. Everything was fine except for the front fork seals and the fact that it hadn't been used for any ride over 20 kilometers for at least 10 years. Everything, including the tires, were still original, so it was obvious it hadn't been used much.
After a thorough cleaning, a change of oil, brake fluid, gas, front fork seals and tires, it looked and sounded as new. Everything on the bike is easy to find and replace. No special tools needed for this. I've used the bike almost every day, also through the winter, and apart from changing a light bulb, I did not encounter any problems. It always starts in less than 5 seconds. Most of the time in 2. Now at 12500 miles it needs a new chain and another rear tire (the front tire is still on 35% or so).
As a first bike, it took me a while to realize that it is still quite a fast motorcycle. Because you can ride it easily and comfortable in the low RPM range, it is a very good beginners bike. At about 7500 RPM there is a nice 'kick' to about 11500. I have tried some of those apps to measure the 0-100 km/h time and it is always around 5 seconds (on different apps, but I don't know how accurate those are), with the best being 4.8 to 104 km/h. Which will keep you ahead of about every car you'll normally encounter. According to the manual it has 84 BHP and can go up to 220 km/h. I have had it up to 194 km/h on the clock so far.
The handling of the bike is a bit tricky; the motorcycle has the tendency to give you the feeling it will fall over when you are halfway through a corner, but you get used to it. It can be a bit dangerous at first, as it is quite scary and might set off a panic reaction when you don't take it into account. As for the brakes; the rear brake is a bit soft and could be a bit more direct. The front brakes are surprisingly effective and easily doseable.
One thing I dislike about the bike is that the 'horse' saddle makes my privates hurt on long rides, because I keep sliding too tight against the tank. Secondly, the choke is only on (4000 RPM) or off, which can be an annoyance for neighbours etc. The bike is also not really made for another person, it is just too small and it makes the handling totally worthless. Another disadvantage are the 16 inch wheels, limiting the tire choice extremely. Finally, the headlights are not adjustable and too high; resulting in car drivers signaling you all the time.
As far as costs go, I think it is amazing that it is possible to get this much motorcycle for so little cash; the bike has cost me €600 (purchase) + €300 (tires) + ~€100 (oil, filter, brake fluid etc.) so far and it is still in very fine condition. When behaving oneself, about 19 km to a litre of fuel is normal. When not behaving, it does about 1:16.
Two of my friends respectively have an FZR600 and a CBR600 from the same era, and although these bikes are a little faster and better handling, the difference is so small that you can still compete and make it interesting. The GPX is a little less sport, but also a lot more tour and commute than those bikes, having better mileage and comfort. And it is cheaper to purchase and maintain.
All round sport-tour motorcycle that is very suitable for beginners. Also a good choice as a commuter.