Berlin

Yes, if you are happy in a big, flat city that runs late. At weekends the U-Bahn runs all night every fifteen minutes, the larger hostels put on something every evening and the queer scene has bars, counselling centres and street festivals with decades behind them. It is harder going if you want instant warmth or a compact old town you can cover on foot.

Amsterdam

It depends on your budget and where you sleep. Amsterdam is small, easy by bike and the airport train runs through the night, but a cheap meal costs around 20 euros and the centre has the worst pickpocketing in the country. It works well for museums, cycling and queer nightlife, less well if every pound counts.