All of my advice is given off of personal experience. Now, I realize that all people with bipolarism do not behave the same, but there are often similarities.
Now I really tried to get to know the person I was with. I made more than enough effort, was more than patient and understanding, more than I should have been. I put up with the mood swings, the binge drinking, the constant lies, the excessive spending for 3 months. I tried to understand what she was going through. Of course, after we broke up, she was engaged to another man not less than a week later to a supposed "friend". I think it would be a crime for me not to at least share those things with a person venturing in to a relationship. Not that those things are going to happen, but the potential exists for it.
On the other hand, if you're into putting your heart into something and then having it ripped out, then go ahead. Personally, that's too much for me to handle.
It is definitely worth the time to get to know the person on a friendship basis, but if you're considering entering a dating relationship, that's a different story. I am personally still friends with the woman that I dated. I still keep in touch with her, to see how things are going. She tells me that she loves me, and wants to spend time with me, even told me she wanted to sleep with me on one occasion, yet she is engaged.