Having upgraded from an HQ16 to an APQS Millennium, I can tell you that you will LOVE the stitch regulators on the commercial machines over the HQ's. The HQ is wonderful, but the big ones are so much nicer.
I personally believe you can learn to use any machine like an expert, and don't necessarily believe you have to try them all out to find the right fit.
I chose APQS for its 8 year warranty, absolutely fantastic tech support, online forum full of wonderful folks always happy to help, and the fact so many of the "super stars" use Millenniums didn't hurt matters either.
I will say that there was a bit more of a learning curve over the HQ, but I couldn't be more happy with my machine. It runs like a dream, is easy to maintain, does not vibrate at all (bad with the HQ I felt) and the stitch regulator just rocks!
It handles any thread I throw at it!