Another 6600 person here, too! I'm very fond of mine, as well. It does everything I want it to do. I've only had mine a couple years but so far it's been perfectly behaved; very reliable and problem-free. Mine is a little persnickety about bobbins - most people say they can use generic bobbins in their 6600's; I have trouble with anything other than Janome brand bobbins in mine - but she's not at all picky about thread.
I've busted needles at least 4-5 times by forgetting I had a straight-stitch foot on and switching to zigzag, and it's never knocked the machine out of timing. My 8 year old niece was turned loose on this machine for 2 full days and when I came back I found the machine still gamely sewing on, even with a bent needle, LOL. Put in a straight needle and she's like new again. This is definitely the most rugged machine I've ever owned!