Most toppers are too thick and lumpy, or become flat and lumpy with time.  This one is thick enough to add a nice padded feel to my bed without lumps or flat areas.  Fits my queen mattress well.  I put a mattress pad over this as well.  Has had minimal flattening after a year of use, I just lightly fluff it when I change the sheets.  Makes my bed very comfortable and does not make me feel hot while I am sleeping.