With exactly the same options selected, the Serval costs 200$ more than the Gazelle. As far as I can tell, the only difference is the finish: matte polycarbonate for the Gazelle vs. rubberized for the Serval.
I know this is subjective, but: do you think the rubber finish is worth the price difference?
(Or is there another difference that I have missed? Remember: same options - including matte screen, now available on the Serval also.)