Originally Posted by
ruby2shoes
I had an 8900 for a short while and although I found the harp space "long/big", it was also "low" and I couldn't get used to it.
I have the 7700 and agree with this. I definitely find my back and shoulders hunching and tightening up when quilting. Because the head is fairly bulky, it can be a little more challenging to use for FMQ if that's its primary use (since the OP mentioned having the 6600 and wanting more space).
If it were the only or primary machine, they are multitaskers. If I were looking for more space for FMQ and already had a good machine for most sewing, I would look more towards the 1600P and its market siblings like the Juki TL2010Q. Straight stitch only, but overall more room to push a quilt into, less head "bulk" to block visibility, and a lot lower cost.