We changed for 2 reasons. One was because Marca was having back and leg issues and found it hard to get on the 2 wheels when I was already seated, and she couldn't bring herself to think it was safe to get on a leaning bike, the second reason was that we knew that somewhere down the road we would have to go to three wheels and if we waited for that day to come we would be too old to get the proper feel and adjust for the differences.
The twisty can be a load of fun, ya you get the feeling that your going to tip over or slide/fall off. One thing I found out is that you need to do exactly the opposite of 2 wheels in the steering business. On 2 wheels you push left to go left, on the Spyder you push left to go right and the counter pressure of the push keeps you solid in the seat. Once you master that the 2 wheelers will wonder where you went.