Technically it is brilliant but for those with LIVE it is too expensive. (and those without LIVE don't need it)
So, why the low score you say, well this disc pack offers little to the casual (non-LIVE player) and the ones that have LIVE could get a better deal anyways.
The pack contains 9 new maps, all of which are beautiful and help to inject new life into the game. Also there are a few documentaries along with some art and the like. While these documentaries etc. sound cool they are nothing special, and offer little in the way of fun. The maps however are GREAT.
Relic -
A large map with a solitary base surrounded by beach. The attackers muct wlak all the way to the back of the base before climbing up it and wlking to the front. This means a bombardment as you approach but if you manage to get the flag off the front you have basically won
Sanctuary -
A small map made of a destroyed building (that seems to be very old) Great for skirmishes and two team battles
Terminal -
A large map with plenty of vehicles and a speeding train to kill you. The only problem is that sometimes in matchmaking you will have a two team battle where you are both attacking and defending at the same time. The thing is the map was designed as a one way battle so those in the garage will have an easier time because it wasn't designed to be attacked (surounded by open space)
Turf -
An Earth based map that is great for skirmishes. One of the most detailed maps in the game
Containment -
A HUGE snow level that features two bases connected by a tundra. A great amp for BIG TEAM BATTLE
Elongation
A remake from HALO, this is a long level with conveyor belts trnasporting great big boxes. Good for skirmishes and HEAD TO HEAD
Backwash -
A stemaing jungle inspired from HALO's "Guilty Spark" level. A real corker with plenty of atmosphere, small map
Warlock -
A remake from HALO, it is a four-way-symetricle map with teleports galore.
Gemini -
A large, dizzying Covernant space ship complete with Prophet Statue.
All these maps are GREAT and really add life into the game......so now the bad stuff
Those who don't have LIVE really wont appreciate these maps for what they are worth. UInless you play with your mates a lot there is no point in buying it really.
And those that have LIVE can now download these maps for free. So, while you don't get the bonus stuff, it is better just to download the maps.
Still if you really will use the maps a lot but don't have LIVE then go ahead as they do make the already GREAT multiplayer MUCH better.
P.S. In my "time spent playing to date" I am showing how much I have used the maps online.