Hi skubaman,
Welcome to the Mattress Forum! 
There is some information about the Gemma Mattresses in post #2 here and a forum search on Gemma (you can just click the link) will bring up more information and comments about them as well.
Post #13 here also has more information about the most important parts of the “value” of a mattress purchase that can help you make more meaningful comparisons between mattresses regardless of the name of the manufacturer on the label which is not nearly as important as the type and quality of the materials inside a mattress.
Phoenix