I definetly recommend test driving as many as you can before making your final decision and ask lots of questions.
With that said My mother has a Gammill and she like it. I was able to test drive hers of course and then also the A-1 and the Apqs Milli and Freedom.
I purchased the APQS Freedom with Quilt Glide and absolutely love it! It was a year old when I purchased it and still under warranty. I have had it since April. It is so smooth and easy to quilt with, with the quilt glide you can micro stitch without missing a stitch.
I have never had a problem with thread tension and just can't say enough about it.
Which ever you decide practice practice, they are so fun..