when they are back in stock these are great. http://www.rednoseusa.com/products/jj_gi/index.htm someone told me they are ATAMA they just have the rednose name on them, a few guys in our school have them and they look the same as ATAMA.
The mount is not an easy position, it take a lot of work to be proficient from it. You could go for an americana and if they pull away go with it and swing into an armbar. It also depends on Gi or no Gi.
no mario sperry stuff yet but a few guys I train with really like it, Roy Harris was up in Rochester NY recently doing a seminar. You know who you should look into is Fabio Gurgel, Gustavo Dantas and Joe Moriera