Well woods and hybrids are completely different. But the loft of your 7 wood is around most 4 irons and the 9 would replace a 5/6 iron. The g5 19 degree would in fact replace a 3 iron as most 3 irons are 19-21 degees.
I would say most of those clubheads are gonna give you the same results, maybe the burner gives you 5 yards or something, but I would think if you don't already have a shaft that fits you and you find one, then you would gain some yards, but your not gonna get any more yards because of a new driver. Over the last 5 years, the average distance on the tour has only gone up 1 yard a year.
They supposively have the hottest faces in golf, if your an accurate shot of the tee, I would say jump on it, if the clubs fits you(length, flex, loft, shaft, etc).