I have not shot the G2 XL, but I do own a bow that is very similar to the Vapor 300.
My Golden Eagle Woodland Extreme Hunter (Vapor 300 riser with swing arm cable guard and a laminated wood grip) is about as accurate as any bow I have shot. It will keep all shots within tennis ball to baseball size groups at 30-40 yards unless there is operator error. This accuracy is with broadheads or field points. The bow gives me enough confidence that I have almost eliminated bad shots by me from the equation. I would imagine the the G2 XL is a great bow and may possibly be a bit more stable due to its longer riser, but the Vapor should get the job done for less $ invested. Good luck with your choice.