So far, I have lifted about 1/4 of my ancient living room carpet. Only to find all of the concrete flooring covered in icky carpet glue.
The concrete also looks horrid because it's obvious that whoever poured it on knew that it would be covered by carpet so they didn't care how crappy it looked.
I think I may just keep it as bare concrete over the summer months. The floor is so much cooler to the touch.
And oh, how I love to run around barefoot (save for all of the concrete nails I've been uncovering).