IMO stick with the G10's...As this game does not seem to be as accurate with spin control than it is with trajectory...i've not played both sets, but played with the Tour Burner Set ( which has the same stats, but and even higher Trajctory than the Tour Preferred's)...and stuck with the g10's. The drop in trajectory was too much for me to deal with, and i didn't think the added spin made up for it. I can only imagine that a lower trajectory set would be even more difficult for me to adjut to.
YJ is right about how the ball flight is affected in the wind, but i still prefer the higher loft with a little more adjustment vs. the a lower flight and trying to judge the roll out instead. Either set you choose, a 5 ,4 ,3 are not going to stop like a PW...
On a side note...can't speak to the i15's...am curious as to how they perform though...perhaps in a few years when i reach Level 69 i'll pick them up.