I'm looking at purchasing an upcut saw. It seems that Whirlwind is popular and there are older machines on the market for decent prices. Have the features changed much on upcut saws over the years? Will I be missing out on any killer features picking up a machine that is 10-20 years old? Also it seems that there are many more more left sided machines that right sided machines (meaning the material feeds from the right to the left instead of what I would guess to be more natural left to right). I'm really curious as to why this is.