there's a subtle bit of contention over what it really does on a bass rod... i think the overall consensus, however, is that if you're building a custom rod, why not pull out all the stops? it doesn't cost anything extra to wrap a rod that way so why not.
Anyway - on big game and surf rods, its pretty clear to see when fighting a big fish on a traditional wrap, the rod twists to the point that the tip is close to being 180* upside down.. just from the weight of the fish. That adds additional torque at the grip to keep the reel upright as the natural behavior of the rod is to flip over... creating fatigue and so on. Wrapping the guides to the bottom relieves this... like on a spinning rod.
That is the primary performance advantage.. it also helps keeping your line from wrapping around the tip of the rod. In my personal experience i feel they are more sensitive - i think it stems from the line hanging on the guides rather than resting on the blank - just my experience though.
Another advantage is that you can use smaller and fewer guides to reduce the overall weight of the rod. I typically wrap mine using 4 double foot guides and the rest size 6 single foots... which saves a few 1/4 ozs when dealing with longer rods that use 9 or 10 guides.
my next rod is going to be a pool-cue flipping stick for myself and i'm going to do a spiral using 2 double foot guides and the rest size 3 micro guides... should weigh less than titanium guides or recoils.
