When comparing Mailbird 2.0 vs Postbox, the Slant community recommends Mailbird 2.0 for most people. In the question“What are the best e-mail clients for Windows?” Mailbird 2.0 is ranked 4th while Postbox is ranked 6th.
Specs
Question Ranking
Pros
Pro Undo send
Pro Free and paid version
Users who only need to use the basic features of the app have a free version available, though it does limit to only 3 sync'd accounts. There is a paid version that does extend functionality and allows for unlimited account but it does cost $1.00 a month or $45.00 as a one time fee.
Pro Snooze
Pro Apps that extend functionality
Mailbird 2.0 supports separate apps that can extend the programs functionality such as Sunrise Calendar, which allows one to add multiple calendars in one view or Evernote which allows for easy not taking and sharing.
Pro Customizable UI
The app is very customizable, you can make it look just like you want.
Pro Touchscreen support
Mailbird 2.0 has touchscreen support for tablets and other touch screen Windows devices which makes it easy to control no matter what kind of Windows device is being used.
Pro One Inbox for all accounts
All messages in one place. But you can select to show only messages from each account either.
Pro Quick Bar for macros
Quick bar allows you to add a variety of content to your message. It will let you reuse URLS in your Sent folder, and autocompletes against canned responses, signatures, and topics.
Cons
Con Collectss user data
Mailbird does collect some user data such as user email addresses, names and client use. So for those that are security minded the use collection of this information may not be wanted and can not be avoided.
Con Way too expensive
Currently the price is at 45€. That's ridiculous for an E-Mail client. The design alone is pretty but neither does that or the functionality in any way justify the pricing.