I use mine daily as my only car, as others have said i'd recommend a late S2 onwards (one with aircon and a hardtop).
The only issue I have is excessive windscreen fogging for the first 5 - 10 mins of driving, but I've only owned my current car for a few months and haven't had a proper look at the fan/aircon to see if all is well. I also don't have a hardtop on yet so i'm hoping that will help a tad.
You will not regret it, especially throughout the summer months when you can take the roof off and throw the car into corners!
I even returned to an Elise (Toyota) after owning an A