Krakow has a TON of history. It is larger than Bratislava and obviously they speak Polish opposed to Slovak (which is like Britannic English vs American as it compares to Czech language). Krakow is not too big to walk around in a day, and has great public transportation– including to and from Auschwitz-Birkenau which was a sobering but powerful thing that I recommend to anyone who ever has the chance to see. Also there is the world famous salt mine which is amazing. The food here is also awesome– my favorite was a huge slice of sourdough, layered with lard that had bacon bits in it, the layered with sliced dill pickles, grilled onions, and kielbasa. All, with a beer, for $3.00 (12 polish zlaty). There are these chain bars that have 1 euro beers/shots/drinks and my friends and I made a point to visit each one in a single night– bad idea, but good time. The castle is also a must see. Also beautiful women here and a lot of WWII history, though Krakow has been peaceably taken over in numerous conflicts through out history.
Went to Prague in the same trip, think a MUCH larger, Vegas-y version of Bratislava. The women are beautiful but not very talkative to foreigners cause there are so many tourists constantly. Excellent beer gardens, food similar to Bratislava. Must see the castle at sunset, hike up (or ride the funicular) to the large tower, and walk along the river. There are awesome bars stuck in the wall along the river that don't open up till about 2000 hours. Everyone brings their own bottles or buys drinks there and DJ's spin music for people of all ages while the sun drops and things get rowdy! Cool jewish quarter here, as well. There is an awesome rock bar that I can't remember the name off just off the main square. The bartenders pour free shots down your gullet, whip rowdy patrons with crops, and are gorgeous. Overall, just be prepared for large throngs of bachelor party-ing, college-aged, loud English/Irish, Aussies, and Americans.
For all of these I recommend AirBnB. There are loads of options and few scammers– just really open, nice folks looking to make some $ off spare properties. The deals are usually much better than hotels or hostels.