They have some really good fast stuff too, like the album "Train of thought" for example. Most of their albums have a mix of fast and slow though. I also highly recomend listening to the album "Awake", it is my favorite one.
Fun fact; when looking for a new keyboard player after their original one left Jens Johansson (who enventually joind stratovarious) was one of the many who auditioned.
@Super speeler My definiton of progressive rock is wrong? I would say its a bit over simplified, but not wrong.