Kathy gave you good advice: Drive them all. This is like buying a car. What works for someone else, may not be a good fit for you. Here are features that I would insist on (and why) if I were to buy again.
Stitch regulator:speeds up the learning process and you get a great stitch from the beginning.
Handles that change positions: this will save your body. LA quilting is very physical.
Hydraulic lift: again, this is to save your body. Sometimes just an inch up or down every hour or so makes all the difference in the world.
Great dealers: they don't have to be in your back yard, just available by phone if you need them. Most LAs are user maintainable and repairable.
With this said, I LOVE my A-1 and would buy one again.