i have the 6600. 9" throat.
7700 - 11" through
i would love to have the larger throat, but i would not trade my 6600 for anything. i love her..and well, i am used to her,and the way she runs..
IF i was starting over, AND had the money..i would go with the 7700.
so i guess, i am no help at all!
other than, you can't go wrong with a Janome..