[ianbannerman]

I've used both. Simplenote has clients for major platforms and the web, unlike Vesper's iPhone only setup. This is the main reason I currently use Simplenote - I need a desktop client (web, OS X, or Windows). But when Vesper's Mac version launches I'd like to switch.

Simplenote offers more functionality than Vesper at the cost of complexity. Parts of Simplenote feel arbitrary or difficult to build a mental model for. Vesper is beautifully apparent in how it works & what you can do. I never feel lost or wrestling for control in Vesper.