Don't worry too much about the sale, they're one of those endless sale companies so there will be a new one very soon. I bought one last year and am perfectly happy with it.
It's pretty firm, but I don't find I get especially hot in it or anything. My girlfriends back problems cleared up a lot after getting it.
The reviews on review centre are genuine - they take you straight there to review after registering the warranty. However I'm certain that memory foam buyer's guide is a 'fake' website owned by a single person, who also has a couple of other pro-ergoflex websites around. I don't know if he's affiliated with them but it's a bit weird / dodgy. I did a lot of digging around with whois etc. to work out the details but I've forgotten them by now..
edit: ah yes bedsforhome.com is the other main website... "we here at bedsforhome.com" all sleep on ergoflex mattresses... all meaning one person, who is the same person as the above website.. meh