I do the 3 for $20 thing with the belts. Actually, its 16 somethin.. We have only broken one and that was because something got sucked into the rotating assembly.
Honestly, the comet belts were not what I expected. The two Ive tried, they last almost twice as long but theyre WAY more than twice as expensive.
However, and this is pretty big. The cheaper belts tend to lose a little bit of gripping power once theyre very worn out. The comet belts didnt do that. It wasnt horrible and nobody except me noticed.
-But there are different "cheap" belts. Im sure some better than others and I have obviously found some decent "cheap" ones.