I bought a couple of Speed Passion Rev 1.1 about 4 years ago. Installed the latest software on them. Never had any problems with them but always had the feeling that the Rev was not smooth enough for me. Tried different setups and once tried to update the software to stock1 but ended up with a malfunctioning esc... I could only change the dragbrake after that
I bought the Rc concept a few months ago and couldn't be happier
. Maybe it's the newer software because latest software update from SP is from 2014...
Price wise they are about the same but I will never go back to SP