It's all about emphasis. Every sentence in my copy has a reason to be there, and the I/We thing isn't it. As it's important to not detract from the real messag

It's all about emphasis. Every sentence in my copy has a reason to be there, and the I/We thing isn't it. As it's important to not detract from the real message, I try and use what I think the reader might expect. This stops the reader from putting too much importance into my word selection on a point that I didn't intend to emphasize. So I use both, depending on the context (although I'm sloppy unless I'm writing copy).