I bought a used 6600MC from my dealer 3-4 years ago and I haven't regretted it for a second.
As a comparison ... I had paid $700 for my 6600 but that included a 60 day warranty from the dealer, and the dealer had serviced it before I purchased it from them. I also got the extension table, the full compliment of accessories it was originally sold with (perhaps 8 feet?), plus a 1/4" accufeed foot, an FMQ foot, knee bar, and soft vinyl cover.
I had recently looked at the specs of the DC1050 when someone mentioned that Joanne's is now selling this Janome model. While I havent' seen/touched the machine, I can only *speculate* that given it's price ($299) and it's weight (12 lbs), it is more than likely constructed of more plastic than metal, so may not be of the same quality components as the 6500MC.