LOL when I saw this thread.
Metacritic has Gears after 28 reviews at 95. And R2 scraping 90 after just 8 reviews.
It's harder to maintain a higher average with more reviews. (well thats logical and mathematically correct as you need to impress more people). I think looking at it it's possible for R2 may achieve less than 90 average. This should tell the story between the 2 really.