When I first started learning chinese, I placed a great emphasis on getting the accent right as well as the tones and pronunciation. So when I was studying Potunghua in Beijing it used to really annoy me when I couldn’t understand people with different accents. It was pretty frustrating paying all the tuition fees and spending hours studying to not be able to used my “standard potunghua” outside of school.
However I soon discovered as previous posters have mentioned, that in China there are so many different accents, that your standard potunghua is not actually the standard at all. So I am not so bothered about my accent now, so long as I used the right words and correct grammar, the accent is secondary.
However I would say that after living in Beijing for 3 years and Taiwan for 2 years, the living environment in Beijing is better at reinforcing correct pronunctiation of characters. After a few years in Taiwan, due to the almost non-existant “r” tone, words like shi become si, chi - ci and zheng - zeng. Re becomes Le, and “f” and “h” gets mixed up.
I rely heavily on pinyin to type in chinese and it gets quite frustrating when I cannot find the word because of the differences in regional pronounciation. It’s also easier to learn the “r” pronunciation and then to remove it when not required than the other way around.
I do live in Taichung so my environment is more local than in Taipei. However the friends I have met in Taipei do seem to have similar accents.
I am from a cantonese/hakka heritage and I do find potunghua as spoken in Taiwan easier to understand than in Beijing. I am not sure if this is due to similar grammar constructs or vocabulary.