It depends on who is doing it to be honest ^^' If it's someone in my family or my close mga kaibigan I don't really mind, but anyone else I find it kinda rude just because I don't know them I guess.
If it's rude, like really loud and unnecessary. In restaurants I've heard guys, young guys burp loudly and it just disgusts me. If it's sa pamamagitan ng accident, it doesn't bother me too much.