I personally really like the 3 smaller maps. It brings some variety to maps, plus they all are fairly large. Not forge world large, obviously, but they are all good.
Impact - That has two large meteorites and a huge empty space in the middle. I don't know why people would complain about this map, plus the UNSC themed pieces look great IMO
Ravine - At first look i thought this map was a little smaller, but then i figured out you could go into the ravine, and around the back of each of the rocks. So, once again, not small. It also reminds me a bit of forge world, with the colours and the pieces remind me a little bit of FW as well.
Erosion - I don't know why, but this one is probably my favorite. I really like the rustic look on this map. Plus, you can build out over the green water (or whatever liquid it is). That doubles the map size or something, after i figured that out.