Electrical Engineer - Should I pursue an MBA?

Graduated from a top 15 engineering program with top 5% grades. Currently a senior engineer with about 5 years work experience in the defense sector and make 85+k per year in a low cost of living state.

I've been aggressively saving and investing my income and by the time I will consider attending an MBA program I will be about 30 years old with a net worth of about 350K. This amount is roughly half in tax-sheltered accounts (Roth IRA, 401K) and half in a taxable account, so I can afford to go to business school and hopefully draw down the taxable portion without dipping into retirement accounts.

I have not taken the GMAT yet, but if I don't crack a 700+ I probably won't even consider applying to any full time programs. My employer will not pay for my MBA, unfortunately, and as a result I'm considering switching jobs to a different company that will in the case where I go the part-time route.

I'm a bit conflicted on the MBA in general -- while I don't hate my current job, it's simply not as engaging as when I first started and there's not a while lot of room for advancement. In other words, it feels like a grind and I'm not particularly satisfied with potential career progression going forward.

Finance wouldn't be an end goal; while I'd keep an open mind, I feel like my background and interests would be better suited towards management/strategy consulting. Plus, the hours in banking are not a trade off I would be willing to make. With consulting, you work a lot throughout the week, but have the weekends to yourself and generally a light day on Friday (from what I've heard). This seems far more preferable to me than 100+ hour workweek where your schedule is erratic.

I believe the MBA would broaden my background and allow for greater career mobility, but the opportunity cost seems a bit daunting. Even assuming I manage to land a consulting gig, with total compensation of around 160K and steadily rising from there on out, I probably wouldn't make a return on my MBA investment until my 40's in a much more stressful job with less security. The return is obviously much less if I work in corporate development or management coming out of school making low six figures (which I would likely be close to assuming I stay at my current job by the time I would theoretically graduate).

There's also the tempting option of continuing to save aggressively and just retire early, although I feel like I'd rather have a fulfilling career that can last me for the rest of my life.

Anyone go through a similar predicament?