If you are looking for the best and most efficient tool for converting MBOX files, I suggest you to MailsDaddy MBOX To PST converter solution.  Below is a discussion of all the features in detail.

Features:

• This solution provides complete data integrity without any changes in folder structure, metadata properties, and text formatting.

• Allow users to view all emails in the mail section, before the conversion period.

• Compatible with over 30 desktop-based email clients including ( Mozilla Thunderbird, Postbox, Apple Mail, Webmail, Eudora, Netscape, Seamonkey, Claws mail), etc. 

• After conversion import MBOX mail in Outlook 2019, 2016, 2013, 2011, 2010, and 2007.

• Many options for exporting MBOX files to PST, HTML, EML, RTF, MSG, and MHTML according to user requirements.

• Add single and multiple MBOX files at one time that can be converted to PST.

• This utility is compatible with all versions of windows os ( 2007, 2008, 2010, 2011, and Windows XP).

• Offers a free trial version for all users to converter the first few items per folder before the software is initialized.

• The user can easily migrate MBOX to Office 365 and exchange on-premises. This feature is enabled only for  Business and enterprise licenses.