Most publishers use fairly weak DRM. Epubor relies upon the appropriate reader program (Adobe Digital Editions or Kindle). I was using an open-source plugin to Calibre, but Epubor seems easier and more reliable.

I bought a book from Taylor and Francis that used VitalSource; I hadn’t been aware of this format; it is horrible. I couldn’t find a workable DRM stripper, but fortunately T&F gave me a refund.