There have been a lot of threads about the Teflon seats. Everyone agrees they wear faster than the OEM steel seats. Opinions differ about whether this is a benefit (better to wear down the seats than the spindles) or a drawback. Some believe that properly greasing the steel seats would alleviate most of the additional wear on the balls. The
bronze-impregnated Teflon seats are an attempt to get low friction with increased durability at higher cost. Neither of the Teflon seats have shown any problems with performance, it's really just a question of durability. If you're not using it as a daily driver or doing a lot of touring, my guess is either Teflon seat will last many years.