Is there a Janome dealer nearby that can service if you need it? If so, my machine like that 6500 has been a workhorse and has a good throat space. I've done queen sized FMQ on it and everything you can think of.
It has all the bells and whistles, thread cutter, needle up/down, needle threader, speed control, knee lifter and I've never had a tension problem no matter what thread I've thrown at it. The only negative is that I felt I needed extra light, so I put an LED strip on it and it's great.
Watson