Just like the title says. I am new to AR's and this will be my first one. What are people's thoughts on used? I know that custom built rifles greatly depend on the assembler, but what about off the rack rifles that are used? I don't "need" this gun, as in it will not fill a particular need, as I have handguns for self defense, a shotgun for home defense, and hunting rifles, but I think that it would be fun to have. Thoughts?