15mm Sci Fi walkers

Hi guys, I have almost finished these walkers, they turned out pretty good for very basic models, I have big plans for the larger walkers in the set, I just have to wheather them around the legs a little, but that will depend upon the basing style I decide to use, I have narrowed it down to 4 styles, each with pros and cons, I plan on making a few 15mm sci fi armies all with the same basing style so I have to get it right.

1) Green Jungle, Pros, could be fun and if done right will look good, Cons, maybe to much work with several armies the same.

2) Grey/Brown rock like the colonial world in Aliens, Pros, will go well with the Xeno force I plan to make, simple, easy and fast, Cons, may be a bit bland.

3) red rock, like Mars, Pros, easy and fast, will give a good scifi feel, Cons, if I get the colour wrong it could look terrible.

4) Urban rubble, Pros, will fit well with a planned Terminator force, could look stunning if done right, Cons, a lot of work over several armies.

Any help or advise will be welcome, cheers.

Walker 1

Walker 2

Walker 3

Walker 4