Ever since these google maps mashups started, I was a bit skeptical about building something for our company that uses the API - I figured it was not wise to spend too much development time and center a large part of our business model around something that can be pulled at any time or changed by Google any way they see fit.
So I purchased a flash mapping system from a company that creates a similar product to google maps and have been developing our website around that system.
Now I'm rethinking whether or not I should use Google Maps or this other system.
GMaps Pros: Unbeatable interface. Will probably be the standard going ahead and people will be used to its interface. Cons: We're essentially at the mercy of Google's whims, which will almost certainly contain ads in the future (possibly for our competitors). The API might change so we may have to keep redeveloping ALL the time.
This other Flash Maps System Pros: We own it and can add different features to it whenever we want. Cons: If streets change, not sure what we will have to do - buy an upgraded system, if it's even available? No satellite view.