Yes, I agree. Weight is a factor. But if your not going to the nats. Who cares?? I haven't seen one contest where it mattered yet. Of course, I hear our district 7 contest may be handled with a scale this year. Might make for a low turnout..
I'm sure you have your experience with advanced Keith, as I don't with electric, still glow back then, but I know people flying Fai, thats could fly with 4200's. It's setup dependent of course. And also flying style dependent. It does take alot of getting used to, I'm sure.
I fly Masters at this point, and use less than 3000 mah, how can 4200's not work for Advanced? I guess if your not careful, I agree. If your new to it, I can see that would be easy, sure. I started with 5300's, found out I didn't need to spend that much. Switched to the 3700's and I'm quite happy although for most they would be marginal in Masters. I wouldn't hesitate to fly the 42 or 5300's in Advanced for sure.

C