I am very happy with the mattress. Whilst firm, as expected, it is very comfortable. It hasn't improved my bad back yet however I'm hoping that over time it will.
I also bought the Breeze base. As with another of your reviewers, I think the option of castors would be a good idea. Another option might be to have higher legs ( or castors). I can't store anything under the bed because the base is so low. Finally, I did think the delivery charge of $180 for mattress and base was a bit steep. I had noted Ebay had offered the mattress for the same price with no delivery charge, although had no offer involving the base. In the end I decided to get both items from Breeze and pay the $180.