What do you like best?
Miro's proven to be a flexible tool to be used for multi-purpose collaborations, concept meetings, private annotations, brainstorming workshops.
They keep introducing small incremental updates, thereby extending the feature set with useful improvements to their product, while keeping the user experience stable (so no annoying moments where you need to look for everything you thought you knew if you haven't used the tool for a while...). I really liked for example the 'meeting-style screensharing functionality to draw the focus to what's relevant and the option to hide and reveal content on the appropriate time.
The real time collaboration with no delay or sync issues is really a game changer, no need to wait for the input of your colleagues or clients to appear, as is often the case with other collaboration tools.
What do you dislike?
I personally stick to the browser version so can't judge for real, but I do hear some colleagues struggling with the desktop version, it seems to be slower in starting up or accessing a certain canvas compared navigating to your canvas in the browser version.
A point for improvement (and I hope the Miro developers get to read this) is the switch between the navigation mode versus the edit or select mode. It's easy to overlook what mode your in and thus some user might accidentally drag or move components or entire frames out of the way, causing some disturbance in the collaboration session.
Recommendations to others considering the product:
Just give it a try, you'll find out quick enough if it's what you need. no harm done in trying.
What problems are you solving with the product? What benefits have you realized?
It allows us to quickly capture the essence of a discussion/idea/concept without much preparation. We're doing content workshops, retrospectives, partner evaluation, process reviews, all using the same simple toolset.