Perfect. If you follow the instructions and put tub on bed of morter, then it is solid as rock. Read and follow the insructions. If your installer won't do that, then get a different installer. I'm a big guy, almost 300 lbs and tubs that move are more than annoying. I replaced a shower last year and it is also perfect. In addition after letting the morter set up for 3 days, I got ready to put up the drywall around the tub and noticed the tub against the insulated outside wall was cold and a draft was coming up from the basement, so I got several cans of Great Stuff and put 2 between the tub and outside wall and end of tub and wall. That warmed up the tub and firmed up the sides. Then I took the 3rd can and took it to the basement and emptied it into the space between the tub and the front skirt of the tub and some between the tub drain hole in the floor and the tub where the morter didnt reach. Perfectly stable tub now.