Totally depends on your market place. Commercial is hurting right now and it may be devalued. You really need to have a firm understanding of the market you live in. All the best.
What is the location? The best way to tell is to do a Comparative Market Analysis both ways. If you email me the location, I would be happy to do that for you. As a side note, be prepared for a tax increase!!!
I had a similar situation here in New Jersey. I had a home, zoned residential that was re-zoned to light industrial. I thought the property, about 7 acres, would be worth more, however, I was only slightly correct. It is all a matter of supply and demand. If there is a lack of highway business, perhaps the value of your land may go up, but if business/retail space in your area is sitting empty, probably not. Your best source of information would be a local realtor who has experience and knowledge of the commercial market.