We didn't look too hard at SimpleGeo but I can say without hesitation that GeoAPI has been fast, stable, cost-effective and easy to use. In the rare cases where we experienced issues they were quick to respond and resolve them immediately. I also know for a fact that they are servicing some very large customers as well (larger than us for sure :).
GeoAPI gives you access to a pretty rich dataset for the United States off-the-shelf, which was very important for us.
We didn't look too hard at SimpleGeo but I can say without hesitation that GeoAPI has been fast, stable, cost-effective and easy to use. In the rare cases where we experienced issues they were quick to respond and resolve them immediately. I also know for a fact that they are servicing some very large customers as well (larger than us for sure :).
GeoAPI gives you access to a pretty rich dataset for the United States off-the-shelf, which was very important for us.