To sell or not to sell: Personal residence

[Brent Perkins]

I have been browsing the forums for a bit now after discovering the Bigger Pockets Podcast a while back. What a great resource! I am hoping you all could chime in on this one:

My personal residence (and our first home) was purchase a few years ago at a great price and now has $100k in equity and total value of $240k. We would like to move into something with more land and I cant decide if we should keep our first house which I could sell with no capital gains, or keep and have about $500 in cash flow as a rental. The thought of loosing out on the primary residence tax exemption makes me cringe. 

Is there some simple math that would make our decision easier? Thank you for your guidance!