My institution had uptodate on the computers, so paying for the phone app would have been a waste of money. Also, asking whether to get epocrates or uptodate is like asking should I get a refrigerator or an oven? They serve different purposes and you will probably need something to fill both roles.
I have never tried the pay features of epocrates, but the free features have pretty much all the drug info you need, including pill lookup which is great for patients who bring in pills wrapped in a napkin. I remember an instance where a guy in clinic was incidentally discovered to have a 200 systolic BP. While waiting for transport to the ED, I asked him if he took any BP meds, he was like yeah, got 'em right here. Hands me a couple loose pills. I looked them up in epocrates and they were Valtrex.