I tried several different sewing machines until I found one that would FMQ well. The first one I ever tried it on was one of the Singer Simples that cost less than $100 at Walmart, and it did a fantastic job! But the harp was so small, I decided to try other machines. I got 2 fantastic sewing machines (Singer and Janome) but they just didn't FMQ. I thought it was *me*, but my husband found a great Pfaff at an estate sale, and it does some great free-motion stuff! It's old, and I'm always afraid it will die on me, so I got an industrial machine and I'm going to try FMQ on it once I get some thread it likes (advantage of Pfaff is that she'll sew with any thread or fabric and the industrial shreds the cheap thread I like to buy!!).
I got all of the machines (except the industrial) for $50 or less, so you don't have to invest a lot of money to find the one that works for you!