My only experience with owning a 21st Century (a Jim and Buddy model) wasn't good. Jim and Buddy still owned and operated the company at the time. I bought a used one from a fellow. The finish was, to put it nicely, awful. I was told this up-front, so no biggie. When I got the bow, I noticed it was strung upside-down, with the larger loop on the bottom. The reason for this was because the string groove was cut wrong on the top limb, and if the top loop wasn't tiny the string would jump out of the groove (this happened).
This was obviously a mistake from the factory, so I contacted them about a fix. They said they would re-finish the bow and fix the string groove for $150 (this was SEVERAL years ago--I don't think I paid that much for the bow to begin with).
I contacted a different bowyer and he agreed to fix the string groove and re-finish the bow for me for $50, which he did. After that it was a great shooter and looked good to boot. I sold it anyway--it was a good shooter, but not great, for me anyway.
Moral of the story here, if it's a J&B bow I'd check it out good before buying. I have no experience with Milton or his bows.
Chad