Softpedia, the famous free download site, published its own review of The Bat! version 4.0. Here’s an extract from this article:
The solutions available right now are pretty good, even in the freebie sector, with Thunderbird or DreamMail doing a wonderful job. But, if you really want to feel the power of a stable, highly configurable email client that knows your needs exactly, take a look at the latest version of RITLabs' The Bat!. You have 30 days of trial and the home version comes at a $35 price while the professional one has $45 written all over the price tag. I know the prices may discourage you, but the product brings a set of features unequaled by any of its competitors.
The Bat! came to a new version recently and, although there are no major changes to its core, most of the improvements are visible as they are liked to the visual part of the application. But you will also feel the changes as they make the software move faster when it comes to message list sorting by a specific criteria and the memory usage is has been significantly improved by fixing various memory leaks (in stand by it now takes a little over 5MB and even when connecting to the server the change is barely noticeable).
The entire review can be read here