With a just an engineering degree you're going to get slotted as an engineer. The starting pay is high but many people want to move out of that so they get an MBA later on, but very few of them are able to relay this into something on the business side (BD/CD/etc. even within their own industry). You can argue all you want about this, it's either being pigeonholed as an engineer or their lack of personal skills/business acumen, but the vast majority of those doing a night and weekend MBA are not going to truly get into the business side and move up. They will be stuck in project management for the next XX years.
And recommending a combined MS/MBA straight from undergrad is a waste of time. No respectable
MBA program is going to allow people in with less than 3 years of experience. And for those outliers that's McKinsey/Goldman experience. Most engineers are going to have a tough time getting into top programs, it's possible, but it's going to be exceedingly difficult.
I would say if you're not going to a top 15 school, it's probably not worth it unless there's special circumstance (if you want to stay in a certain region/if it the school is a feeder into a certain company you want to work at). School is going to cost $75K per year with tuition and living expenses and you're forgoing salary for that time as well. I turned down a top 5 program because I didn't want to take on that much debt and have a hard time to move back to west coast, so it's all a personal decision.