Nowadays, хəрашО (based on the Moscow dialect) is the "standard educated pronunciation", while saying it as хорошО sounds sort of "redneck-ish", as far as I understand. However, this non-Moscow pronunciation has gradually become rarer because of radio, TV, and other mass-communication forms.
"Оканье", the custom to pronounce О very clearly, can be often heard on TV in interview with the villagers of some regions.
In Moscow, many people pronounce А too distinctly where we, Siberians, would insert vague A. If you only heard, the announcement of metro station ДИНАМО. The woman managed to say ДИНАМА, very clear
And I do not even mention here, that in some regions people refuse to pronounce Г (you could lookup some Gorbachov's speech I believe).
"Оканье" in act (not for children under 18!). Every word begins with O!
"Отец Онуфрий, однажды.." - YouTube