Thanks everyone for all your helpful input. I talked with my dealer and one other local dealer, since I want to trade in my long arm. They're working up a value on my long arm. Apparently they lose a significant amount of their value in just a few years.
Anyway, I'm looking at the BL Tiara or the Pfaff sit down (can't remember the name). Apparently from what you've told me here, they're both made by HQ. I tried out the Bernina sit down. It has stitch regulator built in, but from what I understand, the other machines don't. You have to buy it and it sticks with a magnet? Is that effective at all?
I've been vacillating about whether or not to even get a sit down since it feels really different than either a long arm or a domestic sewing machine. I suppose I'll wait to see what my dealer is willing to offer and go from there. I'll keep you updated....