I have had a Janome Memory Craft 6600 for about 10 years and have FMQ about 15 large quilts on it. I love the larger harp space for FMQ and am very used to this machine now. The only thing it does not have is a beep or something for when the bobbin runs low as with FMQ this would be very helpful to let you know so you have time to find a good spot to stop and put in a full bobbin. My husband asked me about a year ago if I would like a new machine. I said definitely not as getting used to a new machine takes a while and at my age, why? I have always cleaned it myself and it has never been in the shop for repairs.
My point is if your present machine has everything for your needs now, why start over? If you have the time and don't mind the learning curve, then go for it. Just saying.