Stadtmitte is probably one of the worst Metro Stations I used during my trip to Berlin, despite…read morebeing in a convenient location for me, basically outside my hotel and on two lines (U2 and U6) the overall station was frankly dreadful.
The station was smaller than most metro stations yet still big enough to have two lines, however one thing I didn't like was it often took two different lifts and walking on street level to get in between the two lines, there was a lack of signage around the station, I even struggled to find the ticket machine and then the signs which say, where each end was going, which was annoying and meant I had to rely on Google Maps due to a lack of maps at the station, which ended up costing me money in terms of using my monthly data allowance with O2, which I'm now able to use in Germany at no extra charge, which is really useful.
The station inside seems a little darker and not the type of place one would like to spend a long time, luckily with the speed of these trains you don't have to, but still the point lies about this station simply being not very nice, far from modern to the point where it seems lifts are regularly breaking down with no other alternative than taking the metro two stops back (I ended up being forced to go back to the station I came from with no notices etc about the lift), a footbridge perhaps between the two U2 and U6 lines or some sort of connection and signage would be better but they don't seem to have that here, that is a real shame and because of this I sadly feel this station deserves a single one star rating.