Your favourite email client is up for an award at the FOSS Awards, here: https://www.20i.com/foss-awards/category/email
As I write, it's currently in first place, but Thunderbird is nipping at its heels! The awards are open to everyone, so support Roundcube by giving it a click (you can also vote in other categories too, of course!).
Voting closes on 31st March.