looking to buy a new trimmer and the salesman at the dealer recommended the Stihl FS 100 RX. This is the 4-Mix type and he liked it better than the 2-Stroke FS 80. Both are about the same in price ($330 for the FS100RX and $300 for the FS80) Anyone have experience with the FS 100 RX or any other 4-Mix trimmers in general?? How do they stack up to the 2-stroke ones, and the FS 80 in particular as far a power, durability, starting, and lifetime?? Thanks!