David Hill wrote:

Which is why I am asking here.
Trying for a couple of minutes in a showroom isn't like using it for
a few weeks.

Well, quite. But equally, everyone is a different size, shape & weight
so whilst I could say "Buy a Tempur memory foam mattress, it's
fantastic" I think it would also be imperative that you also try one
out, however briefly, before spending a lot of money.

So, memory foam mattresses are very good and worth the money but as
everyone is different, try them out first, however briefly. After all,
caveat emptor.

--
Chris