I put a labbed 24p Bravo 1 on my 26' cat (deck boat) with a 496HO, that was running a 24p stock Bravo 1. Rpm with box stock prop during the summer heat was approx 4700 rpm, and with the labbed prop was approx 5000 (boat loaded and heavy).
Speed increase was approx 1-2 mph max, and planing time was slightly better.
In my opinion, unless you are running a high performance boat, where each and every mph matters, labbed props are not worth the extra money spent. You just spend extra for a more fragile prop, and end up beating no one anyway.