I think you are over-valuing him. I picked him up early, but have since dropped him for other prospects. He got picked up in all leagues I dropped him, however.
MIllar is a solid player. He is a .300 hitter with some power, but he doesn't really play everyday, so you fall off in games played. You have to manage Millar more than his worth dictates for me. I'd prefer him on my bench as a fill in for off starters with off days.
* Steroid induced record