It would seem to me that a MBA or MS in Management would be redundant if you already have a Masters in Finance. As a hiring manager I would consider a Master's in Business/Finance/Management/etc to be fairly equal in qualifying someone for management level positions.
Perhaps you should consider something more diversified, like an additional degree in the Engineering or Computer Sciences field.What is better an MBA or an MS in Management?
MBA is more of a general education of business, this is good for being a general manager. MS is more studying a specific area more like your degree in Finance. What it may sound like you will need is a MS in Leadership. Since you are an engineer typically there is a tendency to be more of an intervert instead of outgoing. Just getting another degree isn't going to make you move up faster. Consider something like attending Toastmasters as they have a simple low coast program that can teach you many of the small business practices to move up.
You may also consider reading How to Win Friends and Influence People, as this deals with many of the problems you may be facing.What is better an MBA or an MS in Management?
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The MS degree focuses on one field and prepares you for a staff position. The MBA is a broad degree preparing you for management at any company level. Since you already have an MS the obvious next choice is either MBA or Ph.D. Find the MBA program that is best for you in the Official MBA Guide, a free service.