Why are you ONLY looking at single cam bows?
I used to shoot compound , but now shoot trad and am looking at getting back with a compound to teach and train with my boys who are getting a compound for Christmas this year. I suppose I was thinking a Single cam has less chance of Cam timing problems and easier to draw. I am after a high end Bow for around $500, I don't mind buying secondhand and remember my 62# Marquis being a sweet shooting/quiet bow, come to think of it so was my 65# PSE X-Force . I've owned a few bows, but My Marquis stands out as being the one I wish I'd kept. .
Backing up a step: Do they even still make the Marquis?
In short... Nope!!!!. They stopped around 2009.