We have a good number of AIOs in the rotation right now. Rumpsters used to fit Catie really well, but now they just aren't as good of a fit and there is a little leaking out of the legs. We did have a good run with them though.
I'm really loving my bumGenius right now. It's really an all in two, but I stuff them right out of the wash, so it's no harder than an AIO. The aplix makes them highly adjustable, which is a big plus right now while Catie is chunking up and slimming down every week it seems. I really like the cottonbabies insert that comes with them too.