What is the difference of?

What is the difference of 'ware ware' and 'watashitachi'?

我々 and　私達 are same.
私達 can be read as watashi-tachi or watakushi-tach.
我 is "I". 我々 is "我 and 我". thus it is "we".
私 is "I". 達 is "more than two".

"you" is あなた or 君(きみ）
あなた達 and 君達 has same meaning. those words mean "you of more than two".
in English, the word, "you" can be used both for a single person and more than two persons.
in Japanese, あなた or 君 means a single person. if more than two, あなた達 or 君達.

'ware ware' sounds more mannish than 'watashitachi'. It wouldn't sound too good for a female to use 'ware ware' in daily conversation, although it can be commonly used both by men and women in business/political scenes. In other words, it's safer to use 'watashitachi' when you're not certain about which to choose.

Depending on contexts, "ware ware" may sound self-important; for example, it can be used when a group of persons press their claims.

Among first-person plural pronouns, "watashitachi" is relatively moderate, therefore at a low risk of being taken as offensive.