For me the range of attachment options avialable from Front Runner made it the most versatile rack.
Further they have quite a large "reseller" network, can even get their stuff in LTT at the same price that they will charge you at their shop
My personal favorite is the Eezi-Awn, K9 roof rack. This was the only one i could find that is extremely low but with just enough clearance space flex to load it.
I have one on my G and i'm happy with it. Just placed an order with Front Runner for the rear small ladder as Eezi-awn don't make a ladder for it. And i can still fit in all of the shopping malls for my girlfriend.
Not G specific, but for gutter mount roof racks I prefer roof racks that have their feet spaced so that they are above the A/B/C and D (if lwb) pillars as that is the strongest support area for the roof rack feet. Racks with their feet directly above windows run the risk of cracking the windows if heavily loaded.
A rack like the Hannibal with a continuous plate in the gutter is even better as it spreads the load across the entire gutter of the vehicle.
I don't know which of the racks mentioned in the posts above have their feet placed this way, but it shouldn't be hard to find out.