Both have their pros and cons. Stinsonddog recommends having both and I agree. Google Maps doesn't work with GPS but has a great search feature. BBMaps works with GPS.
Google Maps is more of a location based service locator. You can search for local businesses, get directions, etc. It doesn't do GPS Navigation nor will it locate your position via GPS. Infospace Find It is similar to Google but will use GPS so you don't need to type in your location.
BB Maps is GPS Navigation. It doesn't have search capabilities where you could find local businesses. For GPS Navigation, maybe walking is better with BB Maps but in a car it doesn't work well. The updates are slow, no voice and next turn is poor.
For the 8800 what it is better, BB Maps or Google Maps ?
