Like the last post, I too used Platon with 5/8" T&G in my basement. We had a mold issue in our basement which was initially finished by the builder over 10 years ago. Everything was stripped and cleaned. Then I stareted with laying down the Platon and plywood. After the walls and drywall went up, I finished the floors with a click laminate. Since then, one of the rooms has been turned into a media room. We have used the room for over a year now and the whole family agrees that losing the inch of head room was worth it for the warmth of the floor.
I chose platon and plywood as the cost was about half that of DriCore. The most difficult part of the isntallation was getting the 4x8 sheets of plywood into the basement. The tapcon screws took some work, but I know that my subfloor isn't going anywhere.
The floor was mostly level, but with the platon you don't need to worry about that too much as the large plywood sheets take care of any imperfections.