I'd have to mirror archangels opinion.
Im guessing those are different maps. The most apealing to me is probably the one with the buleforcefield, the lighting is amazing, and so is the skybox adding to the mood briliantly. The city map also looks amazing infact in retrospect, it looks the most promising out of the three(?).
And also, a suggestion for your outdoor alion invasion city map. The lighting (outdoors) make the buildings look alittle bland and i know thats not your fault, getting the lighting to look good on an outdoor map is hard. And no my suggestion, do the map at nighttime. It would be alot more work on the lighting front but it would look so damn awesome. When i did a test city map it looked great! Just imagine iluminated building in the distance, and then the green light streaming down from the alien spacecraft. Seriously, it would look so much better at night! And the skybox in the blue forcefield map, would be so fitting for the city map!
...in my opinion.
If you cant be bothered, or feel it wouldnt be worth it. Can you possibly send me the radiant file? (preferably with this skybox
http://i530.photobucket.com/albums/dd342/prof_flex/shot0055.jpg added... skyboxes confuse me

) I would just do up the lighting, and give it back for you to decide which looks better. Ofcourse this all depends on if you want to do it or not.
Awesome stuff.