I recently bought a Pfaff (not the same model) that sewed beautifully in the store, but now that I got mine at home, it is a temperamental thing and there are some features that are driving me nuts.
Do you get classes with your machine? If so, take it through the paces. What would happen to the down payment if you don't get the machine? As for the reviews: 2 kinds of people post reviews - the lovers and the haters. There is usually a large batch of users that don't feel compelled to review an item. They are happily sewing along on their machine and you deal with whatever glitches happen as they happen.