Flint, I don't know much about that particular model, but I do know about the 4000s. They are strong runners, mine pull 20" b/c's no problem thru oak and ash, just used one the other day on a huge oak stump. I think these saws would do fine with 24" setup as well.
I do notice a big difference between my 3400 and my 3.7 and 3700. I've used a 28" bar on my muff modded 3.7 and had it bar deep in maple, and like you said the saw has the guts to pull the chain without stalling.
I do like the echo saws as well, the ones I've done up are easy to work on and well built. I think the 4000 would be a good choice.