I upgraded from a basic White machine to the 6600 knowing that I would grow into it (also knowing that my husband would not understand if I wanted to trade in my new machine for a newer machine within 6 months), and have not regretted my decision one bit. I use the Accufeed almost all the time, even for non-quilting projects. I do miss the free arm, but I have a little Janome Gem I keep on the side for when I really need the free arm and also for when my 6600 is getting his annual service. I've had him (Edward) for 3 years now and still love it.
My mouth is watering over the 7700, but my husband would never understand and besides that, I wouldn't want Edward to feel left out.