Interesting idea - shame the quality isnt as good as the real google earth - they dont seem to have updated google maps with the latest overhead images from here [Guildford area] (far better quality)
Having had a good look round the site, I've noticed that where "images not available" is shown, if you continue and ignore that, sometimes it continues zooming. Also, it's worth alternating the three buttons in the top left corner as some overide others.
It MAY not be anything like as good as google earth, but for those people with lower spec systems, this is quite welcome.