The problem is that Google wants to see reviews from one of those companies. We're communicating with them regarding this more ... Because this is just a major shake down which will put small dev. shops out of business.
Google completely ignores our complaints about forcing app developers to use just those two firms so any dev. shop using Gmail API (or IMAP over OAuth2) should be prepared to pay >$15k! That is going to drive many small businesses out of business.