If you're determined to escape the clutches (and the license) of Microsoft Office, you should know there are plenty of alternatives. For online tools, Google Docs and Zoho Office Suite top the list, while among offline options, LibreOffice keeps gaining users. Fortunately, there's also OnlyOffice, a name better known for its business solutions, but which offers an office suite that is fairly robust.
It's easy to understand why some users are reluctant to abandon Microsoft Office as their primary office suite. Compatibility and special format details haven't been solved to a level that could be considered "perfect", but we'd be making a big mistake if we ignored the progress of alternative office tools. Everyone knows I'm a longtime user of Google Docs, which does what I ask and nothing more (!), yet many of our readers swear by LibreOffice, and they have good reasons to. Now, I'd like to introduce the OnlyOffice suite, which was recently declared open source.
Documents, spreadsheets, and presentations. The desktop version of OnlyOffice might not be as complete in terms of tools, but the essentials are there. At the same time, I want to emphasize its interface. It's very polished, all the main functions are easy to find, and I have no problem saying that both Office and LibreOffice could borrow one or two ideas.
According to available information, OnlyOffice is written in ASP.NET, and although I haven't noticed any major issues, I did detect higher memory usage compared to LibreOffice. All options related to "trials" and registrations are for the online functions, but I found no restrictions in the desktop tools. While it's good news that OnlyOffice is now open source, it's clear there are things to fix. The documentation on GitHub is hard to follow, some users reported compilation issues, and apart from that I noticed some disagreement between OnlyOffice and LibreOffice when it comes to handling ODT documents and correctly reproducing document formatting. Of course, these are details we'll see solved over time, and as always, we welcome competition. If OnlyOffice and LibreOffice become good rivals, the only thing they can do is improve.