Different areas/groups have different pronunciations for different sounds. To use Torah as the example: some pronounce a cholem as “oy”, which is the same as a komatz with a yud after it. Others pronounce it as “oh”. Some Yekkes pronounce it as “ow”, like you say when you stub your toe.
There are other sounds that differ by group. Chassidim sometimes pronounce a komatz as “oo”, while the majority pronounce it as “uh”.
I’ve heard that the Yemenites have the closest pronunciation to what is actually the original. However, R’ Elyashiv has said that they’re all correct, for the groups that use them.