Interface

        The interface of the Microsoft product is rather bloated with a multitude of buttons/shortcuts to a set of features that most users would likely access rather rarely (power users might appreciate this aspect though). By contrast, the inbox appears rather clutter-free. As for Thunderbird, the most visually disturbing default issue is the small font size of the message box (while the text window can be enlarged, the font size stays the same and it is not particularly obvious how to change it).

Searching

        Appearance and interface alone rarely determine the choice of email client. Users might think to export Thunderbird to Outlook rather in the case when there is a big difference in the provided functionality. Searching is one of the crucial aspects in this respect due to the fact that it can greatly affect the productivity, especially when huge email databases need to be processed daily to extract useful information.

Thunderbird has rather a rudimentary search and sorting options, allowing filtering incoming and outgoing email by:

• sender;
• the presence or absence of an attachment;
• by tags;
• sorting by date, contacts, etc.

Outlook has a much more solid searching functionality by comparison. It is worth mentioning that both applications have good filtering capabilities.

Features

        Thunderbird has always been open source, leading to the possibility for the community to develop multiple plugins and add-ons. Obviously, like with other voluntary community contributions, only a handful of these are really useful and actively maintained. Outlook also has an extensive list of extension to choose from, offering integration with a wide range of third-party services but also a generous listing of user productivity apps (e.g. Evernote). Overall, the quality and diversity of extensions are better for the Microsoft product.

Support And Development

Despite its glorious past and a still relatively large user base, Thunderbird is no more supported by its parent company, Mozilla. Mozilla stopped allocating money for this project already in 2012 justifying this by the fact that it was needed to decouple the two products: its popular browser Firefox, and its email managing tool Thunderbird since the first was taking the financial burden for developing the second.

This uncertainty determined many users to migrate to other well-supported email clients and the top choice in this respect was MS Outlook, a product with a long history and a huge user base of other 400 million. Fortunately, in order to transfer Thunderbird to Outlook, people can make use of specialized software that can hugely facilitate this process.

Conclusion

To conclude, although Thunderbird is a relatively well-rounded application with few caveats, there seem not to be any major areas in which it dominates MS Outlook. This is not surprising at all considering the resources, time, and effort that went into developing the later (it has a huge corporation backing it up). The fact that it is offered as an enterprise solution takes it to the next level in terms of security and productivity demands as the responsibility is much greater.