I've been a fan of Zack Kaplan's sci-fi comics - I can't say he's missed yet. While Metal Society takes its sweet time to get to the point, I think it overall worked as a standalone story. In the far future, robots have subjugated humans, using them primarily as beasts of burden. Tensions between the bourgeoisie metal society and the proletariat humans ensue, resulting in a "winner takes all" fight planned between the feisty and fearless Rosa Genthree and the cool and reserved robot WOL-421313. The stakes of the fight are made clear - a human victory would indicate to the working class humans that they are just as capable as the robots, while a robot victory vindicates the ruling class. I personally didn't feel like this made that much sense, but I rolled with it and had a good time.
The primary issue I did have with this is the pacing - the challenge occurs in the first issue, but then the fight doesn't actually happen until the final issue. So issues #2-4 do feel like it's padding out the story. Kaplan does do a pretty great job making us care about Rosa and WOL-421313, but ultimately I do think the story could have been trimmed down a hair.
The artwork by Guilherme Balbi is solid. I think the subdued nature of the script for the middle issues makes it so that there isn't much in the way for Balbi to work with, but overall it looked nice and made the story flow as well as it could. A solid sci-fi comic overall.