Mailchimp's branding is great and the user experience is nice, except when it comes to actually using their web UI. It is probably the most annoying part of my workflow on any given day. Finding a control for a specific feature is like a bit of a treasure hunt. Their forms editor is a crash course in how not to design usable software.

It's sadly yet another app, which compromises usability for shiny design (another one is Convore).