It's not just a regular client-- we've built out features like mail merge, open tracking, link tracking, behavior analytics, Rapportive-like sidebars, send later, emojis, snoozing, templated replies, calendar invites, and more. Nylas Pro also gives you unlimited accounts, so you can connect multiple addresses.
Folks using Nylas N1 are coming from the productivity world of ToutApp or YesWare. We're really not replacing Office 365 or Google Apps. We're looking at building new powerful workflows for people who live in their mailbox, calendar, and address book.
(I work at Nylas.)
