I have the 6600 and love it. I suggest you join the Yahoo group. there is so much incredible info in their files and lots of members that can answer any question. There are a couple of recurring problems that you may want to be aware of so you dont think your machine is broken. One is that every so often the thread jumps out of the take up lever and creates chaos and bad words til you realize what is wrong. The other is that it seems to have a hard time going over bulky intersections. There is a new foot O2 that helps with this problem. The Yahoo group knows a lot more about this machine than most dealers do!