I did not try the i15 (yet) but I am very curious to see the difference from the G10 I own.
I too went from te raptures' slow meter and approximate precision to, firstly TM Tour preferred, before switching to G10's higher trajectory. I did struglle at first with the faster meter and thought to go back to my raptures, but in time I got the hang of them and now I see the difference these clubs make to my game in order of precision and distance versatility.
In essence, they are faster clubs, but with the help of a GI2 or GI3 ball they can be manageabe and will give a beeter chance at scoring well.
Good luck with your choice.