Cost of cell service in Poland (Who has the best service for the money?)

I am moving to Warsaw in September and I will be there for two years for graduate school. My assumption is I will be foregoing a land line and just getting cell service for my wife and I. We will be using Skype for talking to family so I don't need to worry about international rates. Who has the best service for the money? I'd want our phones to work outside of Warsaw when we go out to see various places, and also when we leave Poland on vacation to nearby countries. How do contract phones compare to prepaid in terms of cost? I know in the US prepaid is much much less but I don't know if that is true in other places. We would be purchasing phones after we arrive in Warsaw, so any advice on an inexpensive place to get the phones from would be welcome as well.

I've heard that Play has terrible conections.My friends are often out of service.I don't know how reliable my informations are.Also Play has the cheapest phone calls but ppl from other companies will be paying more to call you (almost all phone companies are in war with Play) .I have Plus and I rarely have any troubles but from comparison I know it's usually not the cheapest solution.

You probably can't get a contract phone anyway. Contracts with a phone included are two years long, but as your residency permit will not be valid for two years, you can not sign a two-year contract. Although I suppose you could probably sign a one-year contract which doesn't give you a 'free' phone.

I'm with Era and find the customer service to be non-existent (I've been complaining about one fault for ten months and they still haven't fixed it) and I have no 3G signal in my apartment (which is right in the centre of Warsaw). My girlfriend and her elder daughter are both on Play and don't seem to have any problems with signal reception.