Droid Sans was, by Google's own admission, designed for low-resolution screens. It's like Chicago on the classic Mac OS. Looks good on low-res screens but looks cheap on high-res ones.
When I played with a TouchPad and loaded up my own site, my reaction was immediately, “Whoah!” It had suddenly become… playful, and had a whole different vibe than normal.
In this sense, Robotica is “better” in that it is more similar to typical web page body text fonts, and more true to the page creator's intents.
And yet, the DIN-esque aspects of it will have the same problem: Lending qualities to text that the text wasn’t meant to have.