SharePoint 2013 Extranet Recommendation

Greetings,

I have a client who is interested in allowing external users to access project content.  These are users who are not part of their company and do not have an AD account.

We are not interested in standing up another SharePoint 2013 environment in the DMZ.  We would like to use our current internal farm and expose a portion of it.

Does anyone have any recommendations on how to accomplish this?  Reverse proxy and/or 3rd party extranet add-on options?

I am vaguely familiar with SharePoint Solutions Extranet Manager; any experience with this product?  Others I may take a look at?

http://sharepointsolutions.com/SharePoint-Add-ons/2013-products/Pages/SharePoint-Extranet-Collaboration-Manager-2013.aspx?productKey=ExCM2013

Thank you in advance for your input!

Bob Mixon