Hangar 18 is probably my second favorite map of the Annihilation DLC.It's very evenly spread with an open inside and some high sniping points outside.All types of players should enjoy this map.Although it is my second favorite it does have flaws, there are a couple of camp spots and it's fairly small but even then it's still a great map.
Silo is definitely the worst map and probably one of the worst maps in Black Ops.It's the largest map to date and has massive amounts of camp spots.If you're going to play a game mode that requires you to defend something I recommend staying near it.It is "likeable" but probably only for campers.
Hazard is of course a remake of the World at War map Cliffside.This is my favorite map of Annihilation simply because I loved the World at War maps and I'm glad to see one return.It's very cool to see how they remade it too!But still Cliffside wasn't the best of maps I remember it being good for Sniping and Rifles and not much else.
Drive-In is a pretty decent map and can be liked or disliked.Liked for it's Medium size and ability to use any gun class or Disliked for it's camping spots and open space.My personal opinion is it's good if you know how to get around through the outskirts of the map.
Shangri-La can be closed in or open depending how you play.The 31-79 JGb215 is good if you use it right.Shangri-La returns the Bowie Knife and Monkey Bombs as well as Semtex from Call of the Dead .The new Claymores, the Spikemores, are good up until higher rounds but you get two every round and is only 1000 so it's definitely a steal.There aren't any new perks and return all perks from Call of the Dead but the cool thing about this map is every game the perks are in different places (except Quick Revive) which they haven't done since Shi No Numa.There are three new enemies in Shangri-La, Napalm Zombies, Shrieker Zombies, and Zombie Monkeys.Napalm Zombies are annoying when camping similar to George and when killed explode.Shrieker Zombies only startle your screen and have the same health as Zombies while Napalm Zombies have significantly more health.The song in Shangri-La is probably one of the worst, Pareidolia is one of the best songs in BO yet not the best overall.Pareidolia is plausable and enjoyable but not for everyone.
Overall Annihilation is probably the best Black Ops Map Pack yet barely beating First Strike.It's Multiplayer Maps are very good with the acception of Silo.Shangri-La is the best Black Ops Zombies map.This Map Pack is a buy if you're a big Multiplayer or Zombies fan.