Looks like .BERLIN has had one of the strongest launches yet with 31,644 .berlin domains in the zone this morning. (31,645 including the TLD). Just looking at the domains and they look (with a limited knowledge of German) somewhat closer to a ccTLD than a gTLD. If this registration volume is sustained then it is going to overtake .GURU and .PHOTOGRAPHY quickly.
These are the nexus requirements for .BERLIN: [dotberlin.de...]
Proxy registrations are allowed. There is a 12 month usage clause which is quite interesting. (Actually quite smart and should be worth watching to see how it is enforced.)