Depending on your location, I would highly recommend a good local dealer in your area. They are worth their weight in gold if you have a problem, need repair or just help with using your machine. My shop is about 1 1/2 hrs away. They not only offer usage classes, but lots of other fun classes as well.
I purchased 6 different machines until I found my Brother Quattro which does everything including embroidery! (I didn't take the time up front to really determine my needs/use. An expensive way to go!) I have a lightweight Pfaff for taking to classes. Both were second hand machines purchased at about half the original price that were trade ins at the dealership. A trade in machine from a dealer is just as good as new from my experience.
Do as others have said and try many different machines....then buy what suits you best. Just like with cars...there are die hard fans of one brand or another. For me it ended up being able to have one machine that I can use to do most everything I would ever want to do. Make a list of the types of things you want a machine to do...go to the dealer and see all the possibilities. Then prioritize the list to give you a machine you can afford. If the dealer doesn't have what you want... ask them to let you know if they take one in on trade.
Have fun looking and take your time!
Olystar