Micromedex does have a free app version (although, I think there might be a fee now 3-4$ or so), but does NOT include interactions display in the drug info.
Lexicomp & Micromedex (& I am sure many other databases) have almost verbatim sections on side effect info (even ADR%s) with maybe a few minor word changes (thesaurus). Lexicomp & Clinical Pharmacology both (not free) have good, detailed drug interaction sections with scored severity ratings & management as well as data that goes along with the interaction in question.
I can not say there is a single "best" because like others have mentioned, it depends on your work setting. Although I would steer clear of Epocrates for drug info simply because it is pretty bad at omitting information & lacks detail vs. other databases for drugs at least (although the drug info part is free).
