I bought a Janome 4800 and absolutely loved it, but as I progressed I wanted the automatic thread cutter feature, as well as the "cruise control", and larger throat area so went to a Janome 6600. I kept my 4800 and leave it in Florida to use there, but prefer my Janome 6600. When I bought my 6600, the dealer was having a special where they included the table that it drops into to give it a smooth working area, and I also mentioned to the dealer that a friend of mine had received a complimentary travel case on wheels with her Elna, and they threw that in as well.
I love the accufeed, and find that the "cruise control" helps me ergonomically, as I don't have the stresses in my knee, leg and hip from pushing and releasing the pedal. Also, It helps me in my shoulders, as I can sit up straight and just guide the fabric in, rather than feeling I need to use my upper body as much. (It's hard to explain, but it really is better for me physically). And when doing FMQ, I get a much more even stitch when I'm on cruise control. I just find the best speed for me, and leave it there, and then try to get into a very smooth movement with my hands to eliminate long or short stitches from jerky movements. That way I only have to concentrate on one thing (hand movement), not two (hand movement and foot pressure). You get used to stopping and starting with your thumb just by practice. I hope this makes sense, and helps.