We have one also, and I highly recommend you get one Ditter!! With the fibro, it is something that you will find greatly soothing to your body.
Ours is like a normal tub just a little deeper. I would say that you should insist on the inline heater to keep the water hot while you are in the tub. We have that too, and it's a wonderful feature. I would NOT recommend the larger whirlpool tub such as the corner units or 2 person sizes, as most people I know who have those end up not using them because of the amount of water and electricity they require.
My sister had this tub and had steps built up to it on the outside as it was high and difficult for her to get into. If you do this tho, be sure to include a handrail for security. She had the top step made sort of like a bench seat on the edge of the tub so she just sat on it, then swung her legs around to get into the tub. She reversed the proceedure to get out.