I had the same dilemma. In my eyes, both players are equal. So either way, you'll be happy, but at the same time you'll be regretting not getting the OTHER player.
The jog wheels turned out to be much better than I expected on my i5, and they're much more precise and useable than the jog sticks on the g3. It's super easy to navigate the menus. Then again, the G3 is not just a tad bigger and has a battery life of 30-40 hours versus 15-20 of the i5. From what I'm reading on forums, more users are having trouble with the g3 in terms of bugs, lock-ups, etc.
I do encounter a weird glitch on the i5. Sometimes, when FFing through the song, the track slider won't update and stays in the beginning, same with the track time. It *** just fine, but you won't know it from the display. It happens rarely, and I believe with only a few of the files (perhaps due to the encoding?). Firmware updates will fix those things. I haven't yet encountered another bug, thankfully, though others are reporting them with their i5s.
As for looks, it's really nice. The backlights change colour, and you can set a different colour for every mode. I have green for music, blue for FM, gray-ish for menu and red for recording.
When I first got it, I decreased the intensity of the backlights and turned off the JetAudio effects, to conserve battery life.
Anyway, if I were you I would get the G3, it is, as I said, just as good. You already have rechargeable AAs, so no need to waste more money on batteries. The audio quality, menu system and all that is the same.