Just got back as well from Cuba.
Everything's like rankourabu said.

The only issue I had with an Android device is the "unsafe connection" warning, which blocked me good half-hour every time.
Until one of the dozens refreshing of the browser (plus endless user and pin) let it through. iPad worked just fine connecting straight away.

In Havana the spot at the Avenida Italia and la Rampa are the most busy ones, with ETECSA cards sold for 3 CUC.
Outside Havana real shops and real price purchases are possible, with little to no queue, and surfing experience more laid-back.