>>2073870
The two specs are basically clones of each other, except Mech generally gets inferior gear at a slightly cheaper price while Guards gets slightly better gear for a higher price.

Case and point: T-72 vs T-90. Note how for the same price, the 72 actually has a better gun. Mech has a lot of really cost-effective low cost units and I think people will warm to it over time as they feel it out. Right now it's just overshadowed by its fancier cousin.