ORIGINAL: evaderstman
Lots of people like the cv as a begginer engine since it is more controlable. The cv-r is just a ported version with a bigger crank and bearings. And also the x is just a pull start version.
there's a bit more to it than that, but yeah, that's the jist of it.
back when i bought my first aftermarket nitro engine (a .15CVX) I woulda gone with a .12 or .15 CVR, but at the time, they were $160 and $180, while the CVX was $110