One of the things I wish I had done was to "test drive" the machine with a project in mind. For example, the last machine I purchased was an emboridery machine. We ran a test using one of the pre loaded designs, but I find that I get most of my designs off the internet. I would have loved to have done a test using one of those downloaded designs (from a quality site of course). I'm lucky that my machine does stitch great regardless of where I get the design, but I've heard some don't do so well. So, again, my suggestion is to bring your own test to the machine rather then using what the dealer provides. Just a thought.
PS. The next machine I'm looking for is one speicficly able to stitch through leather. I plan to have some leather available to test with. (I tried it on one of my machines after being assured it could handle it... it didn't, but that's ok, I didn't purchase it for leather.) :)