This version managed to convert 160 out of the first 254 from a month of arxiv/math articles, a ratio of 0.63.
The articles drawing diagrams or pictures (e.g. using the
xy package or similar) were not convertible by this version of Hermes, and I don't plan on adding support for them anytime soon.
The rest is fixable and I'm working on it. Letting me know the specific issues you may have in using Hermes for converting LaTeX to XML+MathML+Unicode increases the priority of dealing with them.
As soon as the converted articles will be posted online somewhere on the web, I'll announce here the address of the collection.