Hello and welcome to GMAT Club.
Based on your info, I am not sure that you need to worry about an MBA. Your salary is quite competitive and you seem to be happy in your job. Just keep your job. The primary drivers for MBA are career growth (access to better positions) and switching industries. MBA makes it easier and makes it possible whereas otherwise, it would be hard to get a good Marketing job is you have always been in Manufacturing or Legal.
The primary value of a high end MBA is getting a better chance/shot/option at getting a better job right out of school.
For example - you may get a job that pays $20 or 40K more due to attending a better school (arguably) or you may get a job faster and thus won't have a 6-month break after graduation (which is worth $50K). Employers tend to give preference to higher end brand names everything else being equal. However, if you have substantially more work experience and a solid track record, that will trump a better brandname MBA, however, most often the difference between candidates is subtle. This is theoretically.
Practically, people try to get into the best program they can - they want to have the best professors, best classmates, best job offers, and best name to associate themselves with.