The Legendary Map Pack for Halo 3 is worth the measly $10. The maps are better than the Heroic Map Pack and the new items are very good. The ability to put filters on is pretty cool, but the thing that just puts me into awww is the amount of detail on the maps. Such as on Avalanche with the vehicles having snow on them and on Ghost Town with the rebar being twisted. On a scale of 1 to 10, I would rate the maps a perfect 10. Not only are they fun to play on they also add new enviornments to play on which adds exciting twists to the gameplay.
Avalanche is a snow/icey enviornment with a huge cliff on the end of the map. There are only two, 2-way teleporters and this is the only map were you can use the Hornet. This map is really made for using vehicles. There are your standard Mongooses,and Warthogs there are also 2 Wraiths, but unfortanetly only 1 Ghost. There are several big man cannons which give you a quick boost around the map.
Ghost Town is a wrecked, small city with jungled-up pieces of rebar and stone. It is slowly being taken over by the forest which allows for unique gameplay with incredible detail. There is only 1 sniper, but not much room to use it to its full potential. The map in general is fairly small which means medium to close range weapons would be best for this map.
Blackout is argueably one of the best maps in the whole game it is a remake of Lockout in Halo 2. This map has several vantage points and a awsome background. There is still only 1 sniper, and the standard weapons on this map. Which I fell left a big missed opportunity for the game designers to go all out with some great weapons. However, once you have played this map you will want to keep playing it for days on end.
All of these maps offer great gameplay and for only $10 (I mean who doesn't have $10) are worth the money. Which, when compared to the Heroic Map Pack, is worth the sacrificed to buy them.