I am currently carrying the Federal Hi-Shok 115 gr +P+
(9BPLE). It is "Law Enforcement Only" ammunition, so it is not marketed to the general public. However, surplus lots come onto the market frequently. It has the dual advantages of having a good reputation for effectiveness in actual use, and being relatively inexpensive when it is available. Another nice thing about it is that it is relatively soft-shooting for a hot round. As I understand it, it is loaded right up to the +P max pressure (38,500 psi), and only bears the "+P+" moniker to cover the odd cartridge that, owing to manufacturing variances, produces 38,501 psi or thereabouts.
I have also carried, and will probably carry again, the Winchester Ranger T 127 gr +P+
(RA9TA). It is a newer round than the Hi-Shok 115gr +P+, and develops slightly more energy (441 ft-lbs. vs. 432 ft-lbs.) than the Federal. It also has what most would consider a better bullet. This cartridge seems to be the current ne plus ultra when it comes to 9mm defensive ammunition. Of course, it costs about twice as much as the 9BPLE, and is harder to come by. Every online retailer has been chronically out of stock on it for more than a year, so you'll need to find a store that wants your money more than the love of their Winchester rep (it is also a "Law Enforcement Only" product). Be aware that this load is
hot! Winchester lists the pressure as 42,000 CUP, which is probably (CUP has no direct conversion into psi) around 40,000 psi or better. The extra energy is enough that I bought a heavier recoil spring from Wolff for the next time I use this ammo. Your G17 shouldn't have any problems with the higher pressures, but you, too, might want to pick up a heavier spring if you choose this load.
I have never heard particularly good things about the 147 gr loads in relation to how they work
in my particular type of pistol, and so have never tried them. Intellectually, I prefer the ballistics of the fast 115 and 124-127 grain loads anyway, so I don't feel like I'm missing anything. However, there might be someone out there who has compelling data on them that I have not seen, so I will not warn you off of them.
If money, availability, and compatibility were no obstacles I would absolutely recommend the Winchester 127 gr +P+. However, the fact that I can actually get my hands on the Federal 115 gr +P+, and in enough quantity that I can shoot a fair amount of it at paper, has me going with the Federal 9BPLE for now.