Inside the U-Bahn Station Hallesches Tor, I find it kinda dirty and messy. The station itself isn't…read morea big station but not so small either. It take sometime from A to B, lots of stairs needed to go through. If you are in hurry, better run a little. There are two line go through this station, U1 and U6.
Outside the station, I find it quite cool. The station builded right on the riverside. Because of it, it looks quite different than most of the U-Bahn stations in Berlin. There is a little bridge outside, from there you can have a pretty nice view, whether day or night. In summer time, this is also popular for the birds. They like to build their homes here, quite a view. Some of the city boat tours also will pass by when they returning their meeting point.
There are a library, Poco and Mehringplatz around, other than that not much going on here. If you want some snacks or Take-away, there's a small Döner shop inside the station. I kinda like this station, just when it comes to a rush timing, it could be like in a small race.