Jaya (love your name, btw!), I think it really depends on your height. And maybe how big your belly gets. I get HUGE, lol. And I am 5'9" tall, and really desire my dh in the tub w/me. I need plenty of room, and depth. I also really, really loved the fact that a 'real' birth tub has a heater. However, the one i used had a waterbed heater between the liner and the tub. I imagine that could be easily bought at a waterbed store. I admit I have not seen the bigger fishy pool, so I really cannot compare. For myself, however, yes, 2 inches can make a HUGE difference. It's all about the water covering your uterus completely. And like I said, you have no way of knowing what position your body will tell you to birth in. I would have NEVER expected to be up on my knees the whole time!! I couldn't have, had I not been in water, too! I love to be able to float (and my breasts floated right on top, all proud, lol) during labor--that is the most comforting feeling! If we find that altering our big garden tub doesn't make it deep enough, I will not hesitate to rent my mw's tub. That, of course, depends on our financial situation at the time, too, but it is important enough to me to find a way.