Stayed here recently whilst travelling through Poland with my partner. Getting here isn't too difficult, simply get the train to Centralna and then figure out how to cross the main road (clue: go under it). Once you're there you can work out where the hotel is by looking at the huge inflatable dog as it's in the direction it's looking at.
The hotel has some lovely little restaurants nearby and the key park. Restaurants include a bakery/wine bar, Italian, thai, american and a few others.
Mercure, itself is pleasant on arrival, checkin is straight forward and the place looks spotless. The rooms however, are a little odd. With low lighting, a shower that can be seen from the bedroom (curtain over it if you want some basic privacy) and some black out curtains. It's almost designed for the type of businessman who's into saucy behaviour.
As mentioned, it's a little bit of a walk to Old Town (about 30 minutes?) but is right in the heart of the shopping district. If sight seeing is your thing, I suggest doing a tour of the city via one of those tour buses mainly because a lot of key attractions are tricky to find and so far apart.
Overall, hotel did the job, hotel restaurant wasnt too expensive and the barman was wonderful. Probably wouldn't stay again due to location but for what it offered and the price if booked early enough was handy.
Checkout was a nightmare so maybe education guests on the fast checkout process as we were waiting about 20 minutes to be served.
