As a techie who is doing his own thing, I can see why jcampbell would assume English was not your native tongue. Copy writing is really an art form where it's almost a language of its own. Although your sentences may be grammatically correct, the nature in which they are presented seems unnatural.

To be honest, even if you involved an English professor, the outcome would probably be the same. Asking a native English speaker for marketing/copy writing advice is not the right thing to do. Find somebody who is good at copy writing or learn how copy writing works.