Мне давно была интересна разница, и вот нашел ответ:
DIFFERENCE BETWEEN ので AND から
Another conjunctive particle for a reason, から, is very similar to ので function-wise. They both indicate a reason and the statement that follows them is based on the reason. What differentiates them is the level and type of politeness each one has. から is often used in casual situations or for people who you are close with. On the other hand, as we mentioned earlier, ので is generally used in formal situations, or with people who you don't know well or who you want to be polite with. For example, if you work at tea shop, and want to warn your customer about a very hot cup of tea, you might say:
熱いので、気をつけてください。
It's hot, so please be careful.
〜ください (please) is a polite way of requesting something, so it suits the polite nuance of ので very well. However, this can come off overly polite or a bit standoffish if you're talking to your friends. For casual situations, から would be a better option. And the tone of the rest of the sentence usually matches the casualness.
