I've had my mine for almost three months. Still too early to tell, but for what it's worth my last three months hydro bills were $165, $208 and $144. The $144 was for September and I fired up the tub on October 1st. Not enough data to draw a valid conclusion, but those numbers aren't alarming me.
I've read the concern about hydro costs with Master. If you want jet power (and I do) you gotta pay for it. It's not free. I've also read that they are noisy. Mine doesn't sound that loud at all. Conversations aren't strained by the noise. In fact I like the sound of those pumps...white noise adds to the chill factor. Again, if you want jet power (and I do)....
So far so good by me. The increased power costs are also a lot less then than paying a masseuse lol. I might get a half hour a month from a masseuse if I took those extra hydro dollars to a massage table. I'll take the tub thanks. Always ready and able....and steps from my door.
Each to his own though. Massage therapy isn't number one for everyone.