Hi there! I would go with the deepest pool I could find, tie-dyed, oh, the hot tub sounds perfect! We used a rubbermaid trough. Midwives tend not to like that because it's dark so they can't see how much blood is in the water. My midwife wanted me to get out before I was ready because of that. (*sigh* she was great in general but a little fear-based here -- as if my good spirits, awareness, and energy level weren't enough to know I wasn't hemorrhaging?) With my other birth where we used the trough it was moot because not only did we not have a midwife, but I also elected to give birth on dry land. It was very nice to labor in, though, and because it was dark and high it felt rather womb-like and protected. When there were people in the room, I felt like there was this barrier between them and me (which I wanted -- being touched and feeling watched were distracting to me.)
What I liked about it was being able to submerge myself up to my chest while on my knees. I'm only 5'6" so I don't know how that would work for you, but I know I wouldn't have been able to do that in a fishy pool. Every time I see a photo of a mom laboring in a fishy pool she's leaning back in order to get the water over her.
One nice thing about the trough is its rigid sides -- I could lean on them and, um, bite the edge.
That's also its drawback -- the bottom is hard and has to be padded with something if you're going to spend a lot of time sitting or kneeling in it. Someone suggest a foam pad, that would have been great but I wasn't prepared to deal with the mess of it, you'd have to have some means of drying it out then disposing of it. It was actually fine for me because for most of it I was kind of swimming around as I changed positions, and on my feet squatting (the hard side helps with this too.)