Not the OP, but on my Android device I have an easier time of calendaring since basically any app I choose will show all of the calendars I want (personal, my work calendar, my manager&#x27;s calendar, my team&#x27;s calendar) in the same space.  For desktop, I did have Sunrise&#x27;s desktop app until I noticed I wasn&#x27;t getting a proper sync of some (apparently random) appointments from desktop to cloud&#x2F;mobile, and even more so because I accepted an appointment via Sunrise and it changed my email alias in the response from my actual address to Sunrise&#x27;s generic &quot;invitation@email.sunrise.am&quot; so that people then started emailing me at the generic email rather than my actual address.<p>Most of my calendars are Google Apps.  Outlook was my backup for the work calendar using the Google Apps Outlook Sync app (although I&#x27;ve noticed a few sync failures there, too), and just adding additional calendars to Outlook without having all of my email there too looks like it requires some kind of arcane magick.  Thunderbird+Lightning got rotated out of the mix quickly due to a lot of issues syncing and getting multiple calendars into it.<p>Probably because everyone we&#x27;re communicating with is mixing between Google Apps&#x2F;webview calendar and Outlook or Office 365, I also find that I regularly can&#x27;t see an appointment that is emailed to me in my email client as it shows up as an .ics file attachment instead.<p>So featurewise:<p>- Most important for me: Easy addition of multiple calendars, where I can just select which calendar a new appt should be added, as easily as I can in my Android clients- I hate using web clients for calendaring, and they never really show multiple calendars well.  NOTE: I mean that the calendar has a direct sync to each of the calendars online, not having one main account to which I have to share all of my other calendars.  I want one place where I can go to view and create appointments and then have them also show up in their respective accounts.
- Supports open standards like CalDAV&#x2F;CardDAV as well as syncs to Google or Office 365 (I can select a provider like Fastmail that uses CalDAV for my personal calendar, but I&#x27;m stuck with Google or O365 for work)
- Desktop client, multiple views (agenda, today, week, month)
- drag-and-drop of items into the calendar to create a new appointment
- &quot;Send to calendar&quot; from an email as an option
- Categorization&#x2F;tagging on an appointment would be nice - Outlook allows this but Google doesn&#x27;t seem to allow tagging appointments like you can email<p>A bit of a data dump, but a desktop client that handles multiple calendars well is surprisingly difficult to find in Windows.  I happily pay for a number of otherwise free services (Pandora, Evernote, Pocket, Lastpass, etc.), but there really isn&#x27;t even a pay option.