I was like you a few years ago, and was enjoying sewing/quilting, and knew I needed something better. At the time, I made the leap to the J6600, feeling maybe I went too far. Soon, I realized the 7700 would have been a better option, but did not consider trading as it didn't give me that much more! I loved that 6600 and still do, even though I have since traded upwards again.
If I were in your shoes, I definitely would not buy a 6600 or 7700, and would head straight to the 8200 or 8900. Basically, they are the next generations of those previous two, with some features that definitely make them much more desirable than the 6600/7700. Sure, you would be very happy with them, but you will be even happier with the 8200/8900. Check out the features and see which is best for your future!
I don't know the Babylock line, thus why no comments about it.
As with all machines ... the best thing to do is to go to your dealer and give them a true trial run, to know what you think. Also, consider the long term relationship with the dealer, as to their customer service and follow thru when you need help, whether it be how to's or service and repairs.
Here's a thread from earlier this week, where you might glean some helpful info .......
http://www.quiltingboard.com/main-f1...a-t256299.html