I have 2010 Bluevelo (
www.bluevelo.com) Strada #10 that I bought used in Aug 2014. Comfy Vendetta riding season up here is somewhat short and I had been interested in velomobiles for a long time so when this one came up for sale down in Whitehouse, OH I bought it and rode it home 85 miles. That was fun.
I've been riding it a lot because of carpal tunnel surgery and I did discover that I had to remember to lean/bank on my Vendetta when I went out for a ride after not riding it for quite some time because in a velo you shift your weight in the opposite direction in corners to try and avoid tipping over. Once I realized what I was doing I recovered quickly and went back to banking hard around corners - which I love doing on my Vendetta.
Otherwise alternating back and forth hasn't been an issue. I raced both last year at the Michigan HPVA races at the Waterford, MI racetrack.
They are expensive but immensely fun. With stops and starts and uphills I can hold a higher average speed on my Vendetta (so far) but if there is a lot of relatively flat travel holding 21mph+ For long periods is really easy, especially with the race cap. Starting and going up hill is quite slow. The velo really shines for weather protection and accident protection.
I'm following Jim's TTrike efforts with great interest because I think that would be a lot of fun too although without the weather protection and aero benefit a velo provides. The velo equivalent would be Wim Schermer's Velo Tilt which I will buy if he releases it to production.
-Eric