I think Robo is a fascinating character. He somehow manages to mix the wisecracking style of a golden age super hero with a depth of humanity not seen in most dramas. For instance, in the second issue we see Robo receive a letter informing him of the passing of a man he knew from WWII. This gets maybe three pages, compared to ten pages of Robo smashing giant ants but it does a lot to establish the problems Robo faces as someone who doesn't age. He doesn't pine for a normal human life, but he does care. And this is conveyed without being heavy handed.
Since the comic moves around chronologically we also get to see him evolve as a person. This is most clear in The Shadow Out of Time which starts in the nineteen twenties with Robo alternating between working on his astrophysics degree and listening to campy radio stories, spouting 20s slang and addressing everyone as mister. In the fifties he's a professional in a suit and tie trying to keep Tesladyne afloat, working hard to sound reasonable and in control. By 2009 he's an octogenarian who's been through a world war, the cold war, and a terrorist attack. He's been around long enough that he doesn't hesitate to object to the Quantum Decomputer on the grounds that it looks evil. He knows that he can trust his gut.
I guess the point I'm trying to get at is that Robo is a more complex character than one would guess from looking at him and that Clevinger doesn't go out of his way to tell us this. And I think that's worth noting.