We have the 31L
I initially thought we needed the bunks, with three kids.... I really wanted a bunk for everyone, but we didn't find that the living room layout worked well for us.
With the longer sofa in the plan we picked, it sleeps a kid well without folding out..... but all three kids sleep in the overhead easily for now and a couple more years.
Very limited counter and cabinet space in the living room with the bunkhouse.
The TV located up on the swivel seemed an afterthought and we felt it would get in the way.
I didn't think much of the 31L on paper, looking at the floor plan, but once in it DW loved it, and I have to admit that she was right. It works better for us.
I like the bathroom layout much better in the 31E, for sure though.
Watch that full length slide too, I've read bad things.... although I'm sure they are not all bad, but that is a lot of weight on the slide mechanisms.....
your 31 E will have 28 gallon grey and 28 gallon black.
ours is 29 grey and 31 black..... we find our black tank sufficient, but our grey tank is too small. It fills up quick if theres a bit of dish washing + showers..... and we are trying to conserve with navy showers, etc....
and comparing specs, the exterior storage volume is less.... although depending on dimensions and configuration, that may not be such a big difference....
Are you buying new?
Either way, plan on doing a very thorough pre-delivery inspection
I did a very thorough one, and found several issues that the dealer corrected, but i still found many other things after.... loose and missing screws, drawer slides that worked, but were misaligned so that they failed once the drawers were loaded. And several of the drawer catches that hold them in while driving were misaligned and not engaging..... just mostly little stuff..... but that's another thread......
Good luck with your decision!