As a counterpoint, neither VaM nor Sexlab are what I would consider easy to use, and the dev is doing both custom animations and IK and blending them together, which may be handled differently in those programs (or not at all). Also, the dev is very much just doing this as a learning aid. They're quite active at least, and I guess the goal for the next few updates is to be able to jerk off and blow the horse with realtime reactions/money shots from it. Setting up a scene like that in VaM as a beginner would be a huge chore for most users.