I find most builder will modify a few things to their liking on the bigger ARF's.Depending on what is done this can add little or alot of time.What is probably considered a 20 hour built took me about 40 -50 hours,until I was satiesfied with the plane.
Some ARF's have good techniques and hardware and go together well.
If you crashed your current ARF,I bet you could build a flyable copy in half the time it took the first one