When I was getting ready to buy a new machine, I did extensive research at this site:
http://sewing.patternreview.com/SewingMachine/Reviews - You get honest reviews from people who actually own the machines, including pros and cons. I made a chart and listed the features of every machine I was considering, so I would have a good basis for comparison. I then searched the internet to find local shops that sold and serviced the machines. Unfortunately, I live in the boonies, so the nearest dealer is an hour away.
After weeks of study, I decided on a Janome 6600. I considered the 7700, but my cabinet wouldn't accommodate a machine that large, and I love my cabinet. Plus, for little more than the price of the 7700, I was able to buy the 6600 and a Janome 350e embroidery machine. It's almost 2 years later, and I have never regretted that decision for a minute. The 6600 is a wonderful machine; the dealer gave free lessons on both machines; and she encouraged me to buy the FMQ bobbin case for the sewing machine (which is the best $25 I've ever spent).
The only "con" with the 6600 is that it does not have a free-arm. That was not an issue for me inasmuch as I bought it for quilting, rather than sewing...and my old sewing machine has a free-arm.
Good luck and happy shopping!