The early GT7's had a few issues but the later ones had no problems. I have a KO VFS1, a Novak GTX and a Tekin G10 Pro.

In order of preference for peformance I rate them as follows:

1. Tekin G10 Pro (now replaced by G11 Pro)
2. Novak GTX
3. KO VFS1

The Tekin just feels so much more punchy with the KO being too complicated to adjust

The Tekin looks large but you must remember that it doesn't have a Coca Cola can (capacitor) hanging off the side of the ESC so the footprint is still quite small overall