Personally, I do not like it. I do not like it at all. I found it frustrating and irritating. And while I admit to thinking it was interesting the first time through, even then I recognized that it would irritate me on subsequent playings (I always plan on at least two DS/LS). And it did.
Worse than being forced into another character was being forced on who could be in my party. Maybe I wanted Atton with me on Onderon. (And as an aside, why did I gain influence with him when he wasn't even there? Was he monitoring me? Did the PC forsee favorable influence? Why? Why?! ) It made me crazy. The bad kind of crazy. The not-fun kind.