Just chiming in, but I use MechJeb for boring, routine things that I just don't feel like going through the motions for. If I've got something I wanna test out in orbit, and I'm not worried about the launch, i'll auto-launch while I got make myself a sandwich, then come back and do the thing I wanna do. Plus there's all the information and data you can get from it, some of which I think should actually be stock. Knowing your vehicle weight, TWR, even deltaV, makes learning a lot easier.