7700. I bought mine new in 2010 and it started a whole new era of quilting for me.
I like the large throat and the fact that FMQ seems to always look good--the only time I've had problems is when I've had a piece of thread caught in the thread guide. Getting it out was a pain--but managed each time.
I just sent mine in for the first professional cleaning since I got it and I've used and used it. I do regularly clean out the bobbin area and my DH cleaned out the bottom (where you have to take it apart) once in that time.
However, mine hasn't been "whisper quiet" for some time now. It is the main reason I'm sending it back for professional servicing. It was very quiet when I first got it.
I accidentally took out the wick during my first cleaning. I was trying to be so thorough! Mistake! Am hoping the service people can put an "official wick" back in. I put a piece of felt in there once I realized what I had done.
I have a 12000 as well and prefer the pop out throat plate to the one where you have to screw it out.
I chose a 7700 as my first "higher end machine" because it was affordable but had a good reputation. They are solidly built, heavy duty machines. I've been able to push king sized quilts through that throat plate and not push it around. I did put it on one of those nonsticky mats that helps keep things in place. It has quite a different feel from my previous "hobby" type machines--they sewed fine but were very light weight and I could easily push it all over the table as I was sewing.) This one (7700) is a serious machine and feels like it.