As an 8 year MVP; I can share my experiences with you.
Most (including myself) MVPs are not MVPs by effort - we do what we do; and being an MVP was a nice benefit. It's more of a reward, than a goal. Now, that isn't to say that aiming to be an MVP is a bad idea. The problem with that approach is it seems more like "work".
If the idea of using your personal time to do things like contribute to forums, user groups, code camps, etc seems bad; then don't do it. I do it because I was doing it long before I was an MVP.
As far as pay off? There are a few nice perks, but nothing enormously substantial. For the curious, the actual "perks" are: a 1 year MSDN Ultimate Subscription, access to some NDA information, discounts on some conferences like Tech Ed; etc. The MVP summit is a blast as well. However, there really isn't any monetary gain. Not all companies care (or know) what the award is.
Does it "pay off" for me? I think so, but not for the reasons you seek. I didn't really make that a priority when I started getting involved in the community, nor did most of the MVPs I know, so to me, it was effortless. I like it because I get to interact with other MVPs, learn about cool stuff, and it's encouraging to me that Microsoft is trying to reward the community built around them.