I bought my 6600 two years ago, I had yearned for it since it was introduced. I got it particularly for the Acufeed, and large bed. I am so pleased with it. Free motion is so good on it - the variable speed control is brilliant. I have all the extra Acufeed feet and use them all. It sews brilliantly with all thread. I also got the Janome table for it which is great.
The only other machine I would consider is another Janome!