I like that it is easy to set up, and you can also choose which version control system (Git or Mercurial) your project uses with this tool! It's free as well so there isn't much downside either in my opinion! The only thing i would say about PyUp was when we were trying to add our projects, sometimes if they are larger than 100mb then after pushing them through gitlab for example, once pushed onto Github/Bitbucket etc - all these repos stop working until deleted from PyUps web interface again.
We had many problems adding multiple repositories at first but now its fine :) Great service overall though :). There really wasn’t anything bad other than maybe some initial time taken getting used too? Also initially setting everything else up took quite awhile too haha! But thats just how things go right?!