I have been to Prague but going back for a second time. Quite a few day trips you can also do from Prague.
Wroclaw looks pretty but quite boring with not many attractions for sightseeing.
I have been going to Prague for over two decades, sometimes several times a year, and still haven't ticked everything off. Primarily because it is just the perfect place to chill out.
First went to Poland at the height of the "Polish WG invasion" here, to Krakow. Excellent sightseeing, but not set up to be as tourist accessible as Prague. Having been to Riga, where you can sit on a park bench and see stunning girl after stunning girl waltz past, I was expecting the same in Poland based on the stunners that had come over to London. I was sorely disappointed. But then when every second shop seems to be a cake shop, perhaps not unsurprising. I asked one of the Polish WGs here, and her response was "all the attractive ones have come here, where they can make more money, of course". Unfortunately they are no longer here, but hey ho. Similar in Gdansk, excellent for sightseeing but not much for punting.
It was obvious at the time that most WGs were based in Warsaw (just as most in England are in London, in Czech in Prague, etc etc). Opportunities in other cities, particularly who spoke English, were limited. I also sensed a certain antipathy among WGs to accepting English tourists, I suspect because of their propensity to spend the day drinking and then turn up drunk causing problems. Unfortunately Poland, like Prague and Riga, had become a popular stag party destination, which has done our reputation as tourists no favours. Having said that, I had no issues whatsoever when out sightseeing.
For anyone who likes Prague, I would recommend Budapest. There are a lot of similarities. But if you are having problems with Polish, just wait till you try Magyar.