There may be more GV's out there, but theres a lot more GV pilots..
Whats your goal? contract work? I turn down quite a bit of 7X contract work at $1500+/day. I don't do much, don't register with anyone, and still have been getting calls. Im guessing theres just a lack of qualified 7X people avail lately. Maybe its the same situation in GV world also.
Personally, I might pick the one that my connections in the US fly. Neither one will have an advantage over the other without some strong leads. Not many good GV/7X outfits hire by the rating.
Good Luck!