I haven't seen too much difference between the La Bassine and the fishy pool. It's not much deeper - and really, I think water to your shoulders is a bit too deep for me. It certainly doesn't allow you to nurse your baby after the birth in the pool!
My issue with the AD is the liners. They crease and the floor of the pool is hard. THese creases with the hard floor can hurt knees. I've heard this from many women who have used it.
I'm also a stickler for $$. If you can use something that you can buy that's cheap, that you don't have to worry about going over your due date because it's not a rental, it's comfy, and you can either use it again for water play or throw it away, then those are all pluses.
Molly, your comments about the fish out to get you is funny! I've heard from a couple moms that they got tired of their smiley little faces during long labors.
I think the fishy tub Barbara Harper uses to demonstrate how much better the rentals are is smaller, but not much. I think the key is how the model is positioned in there and the depth of the water. I've never heard of a woman saying she wanted it deeper, but I could be wrong. It just seems like the depth of the fishy pools is just right without feeling like you could go under at any minute.
Of course, I adore Barbara Harper. I have to just say that. We may disagree on birth tubs, but both she and I are just thrilled that more women are laboring and birthing in water!