Just made the switch from Trados to XTM Cloud. So far, it seems like the best thing I've done in ages. As an OS X user, I had to rely on virtualization to be able to use Trados, and I've been looking for an alternative for a looooong time, discarding Wordfast Pro, Heartsome and similar applications in the process. XTM Cloud is pretty intuitive, once you rid yourself of the Trados mindset, and, for a web based interface, it's pretty snappy. QA is not as extensive as in some of the most popular CAT tools, but it works, and the concordance and suggestion tools available seem to work better for me, than the ones offered in Trados Studio. File conversion is not foolproof, but their support is very helpful. It takes a little time to set all the parameters associated with each client, but once it's done, it's very easy to create projects. Word count / analysis and progress measuring is easier and faster than in Trados Studio! It supports all the file formats that I work with (and many more) - Microsoft Office, InDesign, XML, and HTML, as well as XLIFF and TTX for those who rely on agencies sending out Trados formats.
In summary, performance is fast, no stability issues so far (knock on wood), and usability is different, but definitely not harder than Trados/SDLX......I think I just got myself a new CAT tool.