VoG might be the least rewarding, if you ask me. Took me 18 months to get the Foil and the Timepiece. I also know people who have never gotten a Fatebringer and they've been playing since day one. Doesn't sound very rewarding to me. But then again, neither is trying to get a Crux of Crota, so there you have it. If you wanna talk rewarding then WotM is the most rewarding raid in Destiny. Do 2 runs on normal, 2 on hard, open a few chests and all the guns are yours. No reason to ever do it again (thankfully). The problem with KF was that only two guns were ever worth having (the pulse and the sniper), but luckily they were't hard to obtain.