I just got a FlyGrip, arrived yesterday. So far I'm liking it a lot. While the price is a bit high, I think it is particularly suited to a big device like the GN2. With the FlyGrip on, I can securely hold the phone with my middle and ring fingertips at about the mid-point (side to side) of the phone's back. This allows my thumb on that same hand to reach fully to every corner of the screen and to all the buttons at the bottom. Full one-handed access, without risking dropping the phone. I couldn't do that before, and I have big hands. I'm planning on shooting a video of using the GN2 with the FlyGrip. I don't think the video linked above really conveys how useful it is on the GN2.
As a side bonus, the phone with the FlyGrip installed works in my ProClip car mount (which will not work with any case on the phone). There is enough space between the mount and the back of the phone for the FlyGrip to fit. Here's a link to a couple posts I made, with photos, of the ProClip mount:
[Only registered and activated users can see links. Click Here To Register...] I love the ProClip, as it's a very clean and secure mount with custom fit for both the GN2 and my car, but I find the phone a bit slippery without any case. So for a while I was using a TPU case with knurled sides that gave me a better grip on the phone, but I had to remove it every time I got into my car. Now I don't have to use a case at all.
The FlyGrip also works fine as a kickstand in landscape mode, which can be useful for watching a video. I bought the "Large" size FlyGrip, and it will also hold the phone up in portrait mode, but only if I use the lower notch in the FlyGrip, which I understand the smaller sizes of FlyGrip may not have. The FlyGrip also fits into the $12 desk stand/charger I bought, which holds the phone up in portrait orientation.