I'm a big fan of VBLs in cold weather when at rest (I never use them while on the move, pretty much just at camp). I like sleeping in VBL - keeps me warm and protects my quilt/bag. I've been using them with much success for a few years.

Andy Skurka has a very good piece on VBLs on his site: http://andrewskurka.com/2011/vapor-barrier-liners-theory-application/