I went that route.
There are definite pros and cons.
Having your business on your home property sounds nice but it blurs the line between work and home. Works is always there...a constant reminder, it hithers, and draws you in, even on Sundays!!!
When I expanded my business I looked at moving into a storefront. At that point in my life, I just didnt' want to be chained to "business hours"...my kids were young and I was constantly doing stuff with and for them...and trying to keep a consistent work schedule was just not going to happen. So I decided to build on my property. I adopted an open door policy, so my clients come and go at THEIR convenience. The tradeoff of not having an in-town, normal business hours business is that clients come by at odd times, weekends, even Mother's Day. But still not a deal-breaker.
My only advice would be to build as big as you can. I built a 30 x 32 metal building, thinking I would be rattling around in it....I outgrew it quick....wish I had double the size.
Oh...my commute takes 30 seconds....it's 61 steps. :-)