Recs.
Updated
SpecsUpdate
Pros
Pro Consistent development practices
All elementary apps are written in Vala and hosted on Launchpad, and there are standard APIs such as contractor for applications to interact with one another. This is different from most distros, in which apps are written in a variety of languages. This design decision makes it easy to get started developing for elementary and to understand how the various pieces fit together.
Pro Straight to the point
If I had to describe elementaryOS workflow, I'd use three words: Focus, Freedom, Clarity. With the UI that clean, thought-out and intuitive, with animations that seamless and with shortcuts that useful, the very thing separating you and the things you want to do is totally absent. The system just gets out of your way.
Pro Phenomenal multitasking
With the ability to create multiple workspaces, hop between active apps and windows using quick shortcuts and various touchpad gestures, combined with the overall clarity and consistency of the UI, elementary OS provides multitasking experience like no other Linux distro out there.
Pro Active Google+ community
There is a place where elementary users can ask their questions and usually get answers pretty quickly. Not only by the other users, but the devs are pretty active themselves, often engaging in the discussions on the hows, whys and plans of the OS.
Cons
Con No official forums
For some reason the elementary devs do not want to have a forum for discussion making finding fixes for issues difficult to find as the only resource elementary uses is G+, which does not lend itself well to problem solving or large ongoing easily readable discussions.
Con Customizing the look and feel of the UI is NOT easy
Every installation of elementaryOS looks exactly the same without using sketchy third-party software or messing with the Terminal. The only visuals you can change by default are the desktop wallpaper, the dock, and the system font size.
Con Very slow development cycle
elementary does not offer any release date for their stable releases going more with a "it's done when it's done" attitude. Making depending on newer apps a difficulty as well as a poor choice for those that need consistent release schedules for their OS.
Con Window control button placement may be unintuitive at first
elementary OS system apps and apps built to suit Pantheon desktop environment have the closing-the-window button in the upper-left corner of the window, similar to macOS. It may be less intuitive to users coming from other operating systems; however, it prevents you from accidentally closing the window or app when you actually just want to resize it, and adds more mindfulness in your interactions with the system
Con No desktop icons (by default)
The system does not use desktop icons by default, nor is this option available in settings. However, you can still add desktop icons for your apps, files and folders by installing the app called "Desktop Folder". The app is available right in the elementary OS AppCenter: https://appcenter.elementary.io/com.github.spheras.desktopfolder/