Star, The dealer should have a variety of floor models for you to sit and sew. They should be happy for you to take as much time as you want to test out the different features on the machine. They should also have trained service people and accessories. I have a Bernina QE 440, which replaced my 30-year old Singer Fashion Mate. One thing I really like about my Bernina is the knee lever to lift the presser foot.
If you don't want all the bells and whistles, I'd suggest you try to find a Singer 221 Featherweight. Singer manufactured these machines from the 1930s to the 1960s, and they do one thing -- sew a straight stitch (forward and reverse). They only weigh 13-14 lbs. (without the case), so are great for taking to classes. And they are very easy to maintain. There is a Yahoo! group for FW owners and you can get a lot of good information on buying and servicing them. I have a 1939 black machine and a 1955 white machine and I do almost all my piecing on them. The feed dogs don't drop, so you can't do free-motion quilting with it unless you have a cover for the feed dogs, but you can do straight stitch quilting with it. Of course, the throat is very short, so it's hard to handle a lot of bulk. Most FW owners I know use it to piece and have another machine for quilting.