ORIGINAL: Straightarrow
Keep in mind that used bows don't come with warranties, so deal with a shop that will stand behind the bow, if you don't know much about repairing your own equipment. If you are experienced, and know your proper (measured) AMO draw length, then you could buy a bow sight unseen, and make do with it, even if it's a lemon. Also keep in mind that very few bows actually have the drawlength that is marked on the limb. Some vary a little and others vary a lot. A good proshop will be able to get you exactly what you need, despite what it says on the bow label.
I found out about the labels the hard way.. [:@]
BUT I did get to talk to an old fashioned Pro-shop in Panama City, who is gonna let me have a HCA Premier Pro normally marked $549 for $449 since it's last year's model (2003) and set it up and tune it for free
... so I have to choose between it and the Merlin Vision.