Well, I have owned 3 Speedsters and one Spyder. The Spyder handles better than any of the Speedsters I have owned. The Spyder is hard for me to get in and out of, ultimately my wife refused to ride in it any more, so I sold it and bought another Speedster. The doors on the Speedster are wider and open lower also, making it possible for those of us who are less nimble than we once were, to get in and out much easier.
The Spyder is more of a raw vehicle IMO, corners very well, but the top is of no use at all in my case. Impossible to get in and out of the car with the top up unless your are a double articulated midget (excuse me horizontally challanged person) whose full time job is center stage at cirque du soleil. I am 6'1" and 225 pounds...
Most of the Spyders have swing arm transmissions....Speedsters have more space to haul stuff, but I could haul a couple of weeks of groceries in my Spyder, and did so fairly often. In the 6+ years I owned the Spyder I put more than 50,000km's on it, so I drove it often, every day it was not raining....my Speedsters I did use the tops and did get out in the rain on ocassion, a real bad idea in a Spyder, and a not so good idea in most Speedsters. One or more of the Speedster makers offers the car with roll up windows....these days, and have for a while....