I think weight is not a problem. I have a fat airic and the only thing I find difficult to get used to is trying to get down on to it in a confined space. Once down I actually think they are more comfortable than an airbed as they provide more insulation and quite surprisingly I get hot when usin my mat compared to an airbed.
------------- Nigel
March 2012 - Dove Meadows
6th July Moving to Hayle
Amazing family weekend with old steam engines, classic car displays, market stalls, and full catering and bar. And camping on site - Save £25 by booking in advance.