OK, I have New Vegas, and was thinking about purchasing the DLC. My question is if I get all the DLC will my game be any more unstable? I've heard that the DLC makes the game more unstable i.e., more ctds, freezing, bugs and glitches. Is this true?

Yes, get it. Some may have some extra instability, but you probably won't.

Get the Ultimate Edition and trade in your current copy, I think it works out cheaper

I have never experienced any crashes/bugs/glitches from any DLC, some people have but I guess its just luck of the draw

I think it was PS3 users that complained about odd amounts of lag in OWB and Lonesome Road. No bug issues though, so feel free to purchase them.

Dlcs are worth it.

-Cheers