If you can do it part time, I say go for it. I did an undergrad in CS and then did my MBA after working for a few years. At the same time, I started my first company and the knowledge from the MBA really helps. Little things like basic accounting principles to big things like contracts and corporate finance really do help out.

Perhaps the biggest benefit is becoming more comfortable with working in groups where not everyone is an engineer, which is very challenging. Engineers have a certain way of thinking and it's easier to deal with those who think like you.