It's interesting that you mention Chicago; my first impression of Roboto on a 96dpi desktop display is that it looks an awful lot like Geneva (or at least, the TrueType version of Geneva, as interpreted by a modern anti-aliasing font-rasteriser).

Using very dissimilar fonts when Helvetica or Arial was specified (by the web designer) changes the feel of many webpages completely.

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.