I find that this City Navigator NT 2011.40 map (both img and jcv files) is more than twice the size of the equivalent Malsingmaps NT 2011.40 but the Malsingmaps map seems better. At least for my home area, the Malsingmaps map displays more junction views. Although searching for POIs on this City Navigator map takes much longer time than searching on the Malsingmaps map.

Anybody has the same experience? Any reason for the great difference in map sizes?

City Navigator 85,680 kb for map, 358,046 kb for jcv
Malsingmaps 39,800 kb for map, 167,984 kb for jcv