I was particularly interested in Stepanakert because it is the capital of the self-proclaimed Nagorno-Karabakh Republic and I went there because I am interested in the war of independence and in this provinces's geographical situation - in Azerbaijan but not really, but not in Armenia either. But I have to admit that, although the town has some pleasant streets with lots of cafes and restaurants, and some parks, it's not really of great tourist interest as the Soviet influence on its architecture is quite marked.
But because it is a capital it is quite lively for such a small town (about 50,000 inhabitants), and most of the scars of the relatively recent conflict have been erased in reconstructions. If you are going to Nagorno-Karabakh then Stepanakert is an absolute must-see.