I have been to Barcelona, Madrid, Sitges, Berlin and Prague.
I would rate Berlin the best if you want to have fun. Guys are horny, there is a big variety of guys, even hot fit muscular guys and they dont mind fucking just anywhere.
Many friends recommend Tel Aviv which I am going to try next year. They say there are sexy guys who like to get physical.
Bareclona, Madrid - there are a lot of roided up queens from the UK, USA, the Netherlands who like to show off but as for fun they just have a blowjob in the toilet cubicle.
Sitges - like Barcelona and Madrid but older guys and a bit more into fun.
Prague - avoid. Hot guys in Prague are only in porn.
Berlin. Tel Aviv