I think if you search the forum you will find many people running the CVT with no problems. All cars have niggles. VW 1.9TDi and BMW 320D eat there own turbos, but they are popular as hell.
B-class in my view is an excellent large hatch. Out sold the Golf Plus in Germany for many years.
The quality of materials is excellent and the options endless (actually 5.4 trillion combinations possible).
I worked at Rastatt for two years in Halle 4.1.... home of the CST245 - its correct name
Easy to get in and commanding driving position without feeling like you're stilling in a stool.
Go for it.
B200T is thristy. All Diesels are 2.0l but as said the 200CDi was best if not the most popular.