Pros:

Cool maps and forces new strategies to survive.
Awesome upgrades, love the Anti-Tank gun :D
Gunships makes the world go round.
Support players are quite useful.

Cons:

Sandbox:
If I'm facing downwards when placing items, it falls through the map.
Base:
The cannon above the entrance should let me know where it is pointing to in some other way then pressing the fire button.
Mutagens have no way of being controlled and often go off at the worst time possible. 
Multiple items do not appear after being purchased, many times over and over.

Conclusion:

I love both maps, just love them. However several problems is annoying, the items going through the map if not deployed properly in Sandbox is a game-ender. In Base, All support upgrades worked well, however with the exception of Mutagens, very few of the weapons, health and bombs would show up after purchasing, and that's just depressing. I'll review again after any of these problems are fixed.