The new maps are pretty woeful. The topo maps are non-existent.
The maps have changed because Google is now charging for access to the maps. More info can be found here: http://blog.geocaching.com/2012/02/new-geocaching-com-maps/
There's been a lot of debate about the quality of the maps used to replace the Google maps. I for one aren't that happy with the OSM maps for New Zealand. What is worst though is the absolute lack of satellite or topo maps.