I've been keeping track of the alternatives, there's been quite a lot of good, cheap sci-fi terrain released already this year.
2 in particular have caught my eye since they're both UK-based and aren't as expensive as Micro Art.
Sarissa does these for £12:
Or, if you want something with a bit more detail,
Warmill does these for £15:
Both are stackable, have removable tops to put models inside and have a bunch of walkways, girders and other things to go with them.
Having a lot of terrain on the board seems like an absolute must for Warpath due to how deadly shooting is. This problem gets mentioned a lot with Warpath, but I think it's largely down to people not having enough terrain on the board out of familiarity with 40k where a combination of transports/ deep strike/ power armour make it redundant a lot of the time.
I'm used to playing other games like Stargrunt and Urban War where cover is essential, and most of the tactical element of the game relies on it.
