I birth really fast. My last birth, my water broke and the baby was out within 30 minutes, so I don't see myself going to all the trouble to buy, set up, tear down, a birthing tub. I could use my bathtub, I guess, but it's pretty small and I'm just not interested. Besides, with the rate of speed I birth, by the time the tub was filled at just the right temperature, the birth would pretty much be over!
I birthed my son on the floor next to my bed (I had a rug covered by a chux pad underneath me). I swatted down, pushed once or twice, caught him, then climbed into bed and pulled up the covers! It was just fine. No, it was better than that. It was exhilarating!