Queen mattress

You will get all kinds of advice.  Will share with you my experience.  Many have purchased memory foam and they are happy.  I find it does not breathe for me and I get very warm.  The day that we brought home our new 171 I had pre-purchased a European style pillow top mattress replacement from Camping World.  Was $329 delivered.  From the day we installed it, it has been a joy to sleep on.  I am of average height and weight.  It is heavy, so lifting up the bed to get to the storage area underneath is a bit tricky but certainly do able.  I did however, have the thin plywood board replaced with a thicker board and then had pneumatic lifters installed that make lifting it up very easy.  A little expensive mod, but worth it to me.  Safe Travels.