No problemo
As far as I can tell with mine (a '98 GTS F1 with now 32'000km on the tacho), it's a pretty reliable car as far as the essential functions go, and as long as you pay respect to the mechanics.
Make sure that the timing belts have been changed on the one you buy, and then should have 4 years (or 40'000km) of piece of mind, with a yearly oil change (I pay mine 1000CHF=roughly 500£) and the consumables (tires, brake pads).
The timing belts change is around 3500CHF.
Fuel consumption is even reasonnable.
When you buy, make sure though that all the accessories work, these cars are real crap in this area. My mechanics did not yet get the fuel gauge to work accurately, the interior squeaks, I have had a couple of times the gear indicator blinking for no clear reason, and now the front hood won't open neatly because the latch cable is a little loose. You want a car in PERFECT condition and this is not a given, so be picky !
Tires last amazingly long, I've done 13'000km with the rear Expedia S01, they are now dead but they went thru 2 track days, serious mountain driving and occasional (sometimes unexpected) power slides. I just don't do drag starts from a standstill (both in respect for the tires and the clutch). I guess this is the good side of having no low end torque

Fronts lasted even longer, I highly recommend the Expedia S01 (except in cold wet weather where the car gets really tricky as a whole).
Oh, one last piece of advice: buy a GTS. GTB owners have no idea what they miss in terms of noise, the V8 shrieks, howls and mumbles in ways that make a drive with the roof on almost dull in comparison. I hope I am not frustrating any fellow GTB or Modena owner, but the GTS (and the spider too I suppose) are tough to beat in this area.