I've run the gamete, from assembling ARFs to designing my own scale model. It's all fun, but to me, building is a lot more enjoyable than assembling an ARF.
My builds are usually Giant, and Scale. My next build will be a Giant Scale sport model, the BUSA Smoothie XL. I'm currently finishing up a 1/4 Scale Cub, and I've just started assembling a 50 something inch ARF version of a Piper Pacer. The Pacer will be electric. The Smoothie may be, too. The Cub is a gasser.
Like I said, it's all fun.