I didn't play either of them, did I miss out on a great single player experience with either/both? Should I bother dusting off my 360 and grabbing them during my MCC playthrough?
I'm already familiar with Reach backstory (a seamless link to my next point!) from reading the Eric Nylund book The fall or Reach. Its a truly excellent read, tracks story from Masterchief recruitment at age 6 up to beginning of Halo 1! I would advise anyone who hasn't read it to buy it, or if you'd rather save a few bucks you can read it for free here: http://freenovelonline.com/halo-the-fall-of-reach/page-1-121245.html
He also wrote a book First Strike that bridges halo 1 & 2 and Ghosts of Onyx (not sure when in the cannon its set) Haven't read these two but plan to during my MCC playthrough :) --- "You have your way. I have my way. As for the right way, the correct way, and the only way, it does not exist." Friedrich Nietzsche (1844 - 1900)
odst is, sooooo very much... reach? no, not really. I don't mean it's horrible, it just isn't going to kill you if you missed it.
Im on the other side of the coin, i dont consider ODST that good, actually, by far the worst entry in the series, gameplay and story wise. While Reach was probably one of its best, ive read Nylunds book as well, its still definitely worth picking up Reach.