I've been using other GForce batteries for a while and have been pleased with their performance and price.
So when I started looking for replacement batteries for my foamys - and the brand I had been using was out of stock - I decided to give these a try. The arrived quickly (though Value Hobby only about 50 miles from me) and were well packed. I've already run several cycles through them and they met my performance expectations.
I can't comment on longevity at this point, but my other GForce batteries have held up as well as more expensive brands so I'd assume these will too.
Based on my experiences with them, I've been recommending GForce batteries to my flying buddies.