Thanks David - we will definitely try and cover that somewhere on the site. I expect that in the majority of cases people who are comfortable with Google's terms that Google Maps would definitely be the right way to go - they've got a great team and build an awesome product.
Most of the interest I have had with Tile5 locally has been with GIS providers that build mapping systems that are for use within the confines of an organisation (i.e. not for public websites). In these cases you are required to purchase an Enterprise agreement for Maps and for some people this just isn't cost effective.
In these situations the fallback choice is either something like OpenLayers or a mapping vendors own mapping library. Most of those libraries lack the polish of the GMaps library.
Will definitely try and come up with some words that capture this for the tile5.org site.