I love my 6600 and find it an easy machine to use. BUT the manual is very bare bones basic and I am sure that there are features and stitches that I could be using more if I knew more about them. I also find a local dealer to be valuable. Some dealers will service any machine and some will only work on ones they've sold. Not that a new machine will need anything more than a good cleaning and service, but still....
See if you can get the price down a bit and buy from the dealer if you can.