Which memory foam mattress is better? I am planning to buy new memory foam matteress. I looked for William's...

I am planning to buy new memory foam matteress.

I looked for William's Loft Nuture bed and Costco NovaForm.
Which one is better to use? :)
Is this a Wasp?
Answers:    Things to look for, check the density of the memory foam the highly developed the better say 5lb if you are looking for a full mattress get hold of one with an extra seam of memory foam in the pillow top, to be precise what I have and I love it, I enjoy had mine for almost 2 years and it is the best mattress ever.
You should hold a look at this site
http://www.sleepzonememoryfoam.com to gather info on what to look for, they individual sell from within site in Australia and United Kingdom so if you are not within one of those countries you can't buy.