I have the map in my B&G Zeus 2 chartplotter and had an update installed by SVB in April 2025. The price of €146 for the update, including shipping, is reasonable.
I mainly sail in the Northern Adriatic region from Lignano via Venice and Ravenna to Pula, and I'm satisfied with the resolution and level of detail. I use the D&K map set of the Northern Adriatic as a backup, along with a few Italian lagoon maps. The C-Map map doesn't come close to their information content, but it doesn't need to.
The C-Map map is in no way inferior to other electronic maps of the Northern Adriatic from other providers that I know from boating neighbors.
Since I don't sail in regattas, I only need the basic features, and for that, the map is more than sufficient.
Due to its extensive coverage, it's also sufficient for significantly extended trips beyond the Adriatic.
I am completely satisfied with the C-Map map. This is my personal opinion, others are welcome to have a different opinion.