That map came out within the last month. I have only read one report about it over on Groundspeak and the user liked it.
I suppose "better" is subjective. I have not seen this map myself, but it does contain full routable roads, like the City Navigator maps. The files here (or most of them) are not routable and cannot be used to give you driving directions. I suspect that the POI's are much more extensive on the Garmin map, but don't know for sure. People have complained about a lack of trails on the 24k Garmin topo's, but I'm guessing this could also be an issue with the maps here since that data can be hard to come by.
The 24k topo's are copy protected since they contain Navteq data. If you purchase a pre-loaded data card then it can be used in any GPS, but it cannot be duplicated. If you purchase via download then the map will become locked forever to the GPS that you install it on and cannot be used in a different unit.
They don't seem to be offering this map on DVD. That means you cannot use it with Mapsource. Neither the storage card or download work with Mapsource, only on the GPS itself.