Heres my thoughts on the maps so far.
Highlands: Huge map. Perfect weapon placement on both sides. Many routes to take so this will give snipers some fits. Background images are a sight to behold. Hearing the Covey ships glass the planet while fighting gives it a real battlefield feel.
Condemed: A large map for 4v4 slayer matches. Power weapons are kinda hidden so exploring the map before playing would be a good idea. Its an ideal map for CQC. Sword and shotgun will be key for winning. Low grav area is an instant death zone lol. Which ever team can get the rocket launcher will see a quick swing of kills in their favor given the tight halls. Looking out the control room window shows the space battle and is worth taking a sec to see the wonderful work done on it.
Unearthed: Biggest firefight map on Reach by far. Possibly bigger then Lost Platoon on ODST. Played this map with Strife and we had a blast. Many places that you can go into that you wouldnt think you could. Using the rocket hog with less then 4 ppl will basically get you killed very quickly. Dropships spread the troops out dont use the target locator on it like you would do on other firefight maps. Give it a few seconds and the Covey troops then to group up to attack then you can TL them for the big kill. Map looks wonderful and future DLC firefight maps should follow its example.