There are many buttloads of threads comparing them.

But anyway my opinion: I recently converted from Chromes to TI's. The Chromes are stiffer, and tonally they start off brighter than the TI's, and darken/warm up noticeably over time, whereas the TI's are reputed not to change so much over time. On a fretless, which is mostly what I'm playing lately, I like the extra flexibility of the TI's. I think on a fretted I'd prefer a stiffer string to avoid fret buzz (although I've read here that a slight change to playing technique can also eliminate fret noise with the TI's). The low B of the TI's has a fuller fundamental tone than the low B of the Chromes, IMO.