As someone who used to use ROOT, I would strongly recommend against it. Its C++ implementation has all manner of hidden state, and this leaks into PyROOT.
For example, ROOT has the concept of ownership, entirely distinct from the python sense of references. A file owns the histograms that were read from it. Closing the file changes all references to histograms read from that file to None. It took a large amount of digging to figure out how that was even possible (overwriting an existing object from within the C API), but I cannot for the life of me understand why.
ROOT has way too many gotchas for me to ever recommend it.
Yeah it has a lot of state that's not very pythonic (and I almost always use it from c++ or cling) but it is very good for semiinteractive plotmaking that's not possible in something like matplotlib. A lot of ROOT's legacy from the 90's shows, but ROOT6 has made a lot of progress.
Does anyone outside of High Energy Physics use ROOT? I'm not trying to be argumentative, I'm genuinely curious, I'm a physicist by day so seeing ROOT talked about on here amongst popular libraries is like someone recommending my local pub as the best in town.
I used root in astrophysics for a couple things, but that's hardly outside it's intended audience. yt is generally considered to be easier to pick up now instead though.
ROOT and yt have quite different domains (although it's probably possible for each to emulate the other...) so I'm not sure it makes sense to compare them.
