LOVE IT.  I have the dress on right now as I type this.  It's super comfortable and forgiving, resists wrinkling well, and looks great.  It's very figure-flattering, and has a nice retro flair to it.  Bra and underwear lines/show-through are not a problem at all.  I bought the dress 10 lbs. ago, and it looked great on then, and even better so now.  I'm 5'5", 125 and a 34C, and I bought a M.  It still fit just fine when I was 135.
I've washed it three times and it seems fine; something about the feel of the material makes me worry that it may begin to pill after a while, but for the price, I'm willing to run the risk.