I had 2 bad experiences with Discover Cracow, recommended in the RS Poland book. I would not recommend this company to anyone.
Trip to Auschwitz - I paid for hotel pickup & drop-off. The overall communication from the company was nearly non-existent. Thanks to my Poland tour guide, this company sent a taxi to Hotel Grodek to bring me to the bus. The bus guide, Ilona, barely spoke the entire drive to Auschwitz (and back) so we had no idea what we were seeing or what would happen when we arrived. On arrival we had time to use the restrooms, then meet prior to the tour. We waited a LONG time - our Auscwitz guide was at Birkenau.
She finally arrived. Although fluent in English, her accent was so heavy I probably understood 60% of what she said.
Be aware - there is a LOT of walking at Birkenau....but I'm glad I had the opportunity to visit both. Dropoff was NOT at my hotel - it was in an unfamiliar location.
Trip to Wieliczka Salt Mine - I paid for hotel pickup & drop-off but Discover Cracow refused to sent a driver to the hotel.
The new guide (Kate) told me twice in writing to meet at Wielpole 2, which turns out to be in front of the post office.
I waited 30 minutes and finally called the office. Turns out everyone else was back at the previous day's drop-off! So they sent 2 taxis to get me. #1 - no show. #2 - woman didn't want to let me in until I asked her to speak with DC. Thankfully, everyone on the bus waited for me to show up (20 minutes late). The salt mines were incredible - be prepared for a LOT of steps and long walk back to the elevator. Tour guide's map and video to return to the bus were useless. 8 of us were lost. She found us...and the final 2 were 20 minutes late getting back to the bus, so my 4 pm private ticket to the Schindler tour was 20 minutes late. I will mention that I purchased that Schindler ticket in advance after confirming what time DC would return. They missed the mark by 1 1/2 hours.
Overall, Discover Cracow's communication and guides were not good. I suggest your hire a private guide or book your own transportation.