Differences with English varieties?
As you know, there are many different varieties of English. The distribution of stress is fairly regular across the various varieties, but you should know that there still exist some differences.
For example, there are a few difference in word stress in words of two syllables that end with -ate in British English and American English. In such words, the stress falls on the last syllable in British English, and on the second before the last one in American English. Thus, rotate is pronounced roTATE in British English and ROtate in American English.
There may also exist slight variations of stress placement in varieties of English that are more closely related. For example, the word police is generally stressed poLICE in General American English, but there are regions where it is stressed POlice.
The fact that stress can be different between various varieties of English should not be a major issue as far as we are concerned since the differences are quite minor. Simply keep in mind that regional variants in regards to stress placement do exist.
That said, if you want to go further, check out this page which outline most of the words that are stressed differently in American and British English.