Cog style V-belts last longer. I used to always order Browning from Grainger/Zoro, which are great because you can tighten the living crap out of them when you install them and they barely stretch. I bought a bunch of Gates from VBeltSupply.com at half the price, but you have to go back after a month or so and tighten them no matter how tight you got them before because they stretch so much. I've only been using the Gates for a couple years so I don't know how they are long-term. The Browning last at least ten years as long as they're tensioned properly. Don't use A-width belts unless you run two per pulley. A single A-width won't grip well enough to run a SS bay pump, it'll just turn itself to powder and need to be tightened over and over.