From paper form (pro shop comparison) there seems no substancial difference between the two:
Equal in high trajectory (good) and spin, distance only 8 yds apart, advantage R11 concerning forgiveness, advantage G20 concerning meter speed. The G20 is 100 cr more.
My intuition gives the G20 an advantage because of the higher release level, but that's only a feeling.
Take the lvl 69 Rocketballz into the comparison, it's another 100 cr more, only med trajectory (bad), mere 5 yds longer and no further substancial advantage to the others - not a club that I'd chose.
OTOH, there is the lvl 68 i15 3WD with good price&numbers, yet a fast meter. If you can handle it it might be the best in the comparison.