Hi happy to provide some perspective here, as an Ex-OW Middle East consultant.
Not surprisingly financial services is quite a large part of the firm's business; however, the work is more focused on financial services strategy and operations vs. running due-diligences for private equity firms (which is more Bain's bread and butter).
Other large sectors for the firm include Energy (compete quite well here against the MBBs of the world).
Public sector is also a very large and growing practice. The firm has large accounts with GCC governments (think Ministries, crown corporations, etc.).
Additionally Telecos are also a sizable chunk of the ME platform, with several big name clients in countries such as Iraq, Kuwait, and Saudi.
Hope that helps - feel free to DM me if you had any other questions!