I've got a 2.2 JTS Spider and (touch wood) mechanically it's bullet proof. I've had no problems with it breaking down or giving me any problems that stop me driving it.
It does, however, just do funny electrical things. Mine is looked after by an independent garage called AHM in Hampshire and they've pretty much said to me that it just goes with the territory.
Some examples are:-
It tells me the roof has failed when it hasn't.
It sometimes tells me there is no oil in it at startup, when there is defintely oil in it.
Currently it's telling me the brake lights have failed... and surprise surprise, they're working fine.
I'd like to sit here and say "Oh but it gives it character so it's all fine", but in reality it is quite annoying.
However, if you're willing to overlook these sorts of things you will definitely not regret it. Driving it never fails to put a huge smile on my face, and I've had it for a year now and I still can't help looking back and checking it out after I've parked.
Frankly, there is only one thing I would trade it for, and that's another Spider... but one where all the electrics work properly.