CATIA is probably the most preferred 3D modeling tool in the automotive and aerospace industries. This specific surface (it can be handled well by the experienced users) is well suited to use parametric design principles and hence result in great products. One of the issues we have in the automotive industry is to work with large surfaces for body exterior (main body, gate, hood.) or interior trim (door, headliner.) panels. CATIA enable us to design surface perfectly through the lines. Also, assembly features for intricate designs (gearbox, exhaust, engine, suspension.) are more than adequate. I did not find any inefficiency while designing products with CATIA. Only the interface and handling of the menu and mouse is not the best - or at least you need time to get used to it.
I generally contact with IT or internal CATIA support team, so I cannot comment in detail. I remember we have struggled to move to v6 update, and it required a long and detailed work to update all the systems. There were some times we had limited support from Dassault, but it is normal for a company of our size. So I cannot criticize much.
Once major advantage I realized when using CATIA is surface modelling, and modifications or changes in part model later. SOLIDWORKS provide a really good and quick way to part modelling. However, part modifications and assembly modifications take time. In CATIA, complex geometries can be easily generated, when compared to SOLIDWORKS. Managing and updating designs of large scale models and complex geometries made me realize an advantage of CATIA over other CAD software.
The ease of modeling helps a lot to save time, in both modeling new parts and also assemblies, which in the end makes a great positive impact on the development.