For one thing, not everyone gets extra weight on their total from using a belt; I know several lifters who stopped using a belt after realizing that their beltless max was actually higher.
For the short while I've been lifting, I have found that every time my belted max went up my beltless max also went up. Using a belt enables you to use more weight, for one thing, and increases your midsection stability while still strengthening your abdominals and lower back.
The main thing to watch out for is that you still utilize your best technique with the belt. I only use it for my top sets (around 90% of my max).
I would say that if gaining strength is your goal, weight belts will definitely help. As far as what kind: Anywhere between 8 to 13mm thick, leather, and the same width all the way around. My personal preference is a double-prong, but lever belts work nicely too.
Form follows function.
Last edited by IronManlet; 04-11-2012 at 08:08 AM.