I voted Grip, but that's just preference. I know a couple local players who use a Golf Mahal. The most recent versions are very quality bags. I won't argue that. It's just WAY too much bag for me.
So I will say it depends on what you carry regularly and what you're looking for. I only carry 14-16 discs and the storage on the Grip is plenty for me. If you carry a lot of stuff, look into the Mahal. The worst thing you could do is buy a Grip because the majority says it's the best and realize you need more.