There are a number of good sit-down mid arms and also long arms out there now that you can try if you go to a large quilt show. Before I got my used Sweet Sixteen I tried just about all of them out and they all seemed good to me-- but I tend to get along well with just about any sewing machine out there. I would have gladly bought an Innova, APQS George, BabyLock Tiara (made by HQ and essentially identical to the Sweet Sixteen), Bernina sit down, etc. if there had been a used one for sale in my price range. As it was, I lucked into a used Sweet Sixteen with very little use and the extras I wanted so that's what I've got. I have to say that I did not like the stitch regulator on any of them, but you should try out the ones that are available on each machine if you feel the need to have a stitch regulator.
Rob