I’ve heard that there are issues with the more recent versions of Python (3.x?) that have led to slower adoption. Is that true? And if so, is it an issue when different people are using different versions of the language? Which version of Python is most widespread?
Does Ruby have a similar issue, or did most people switch to 1.9?
Please note that this is not a general “vs.” question at all, but rather a question about this specific issue.
As far as Python, most people are using the latest version of the 2 series. Python in general can be a nightmare as to mixing versions (at least, it used to be), but the solution is simply to deliver your software with the entire python environment it depends on.