I use mechjeb 'cause i like it more than KER. The windows are harder to read, but i like them. The autopilot is a little bit cheaty but in some cases it is very handy It is very reliable, i've just encountered a first freeze in mechjeb (today). I deleted KER because it freezes. I really like the pod with the strange eye in it. To be short, I think mechjeb is a lot better than KER