I have both and, while I do love Gigi, I actually recommend the G-Ki over Gigi.
The G-Ki is not only wonderfully stimulating, it is adjustable to better provide your desired angle/pressure. You can actually adjust it to get simultaneous clitoral and G-spot stimulation (kind of like the Groovy Chick or Rock Chick, only better). I also am able to obtain a further reach with the G-Ki, for deeper penetration (you get a much more shallow penetration with Gigi). Plus, the G-Ki is waterproof (Gigi is not). Like Gigi, the G-Ki is rechargeable (with a really cool magnetic mechanism that just clicks onto the control buttons). Additionally, the G-Ki feels just as high-quality and luxurious as Gig, IMO. Finally, the flat angled head of Gigi can catch on your pubic bone. I have had no such trouble with this when using the G-Ki, so I can thrust better with it.