If you're going to buy one built up, be sure to ask about the movement too... has it been serviced? How does it work?
I bought a magnificent build and just heard from Ziggy that there were screws loose, screws missing, chipped pallet exit stone, the wrong pieces installed, stuff like that.
He did a spectacular job for me and put it right, but for less money I could have thrown away the movement that came with the build, and sent a tired old 2784 for cleaning and service... and had a better movement.
Lesson learned... I didn't specifically ask about the movement when I bought it.