The majority of engineering lectures, labs, classes, etc happen at the department anyway, so it doesn't really matter which college you go to, as long as it's not too far from the Keble Road triangle.
I can't really comment about rowing, not having tried it or paid it much interest.
I hear the Oriel is indeed good at that sort of thing though, and we seem to do well enough at Engineering. Dr. Hamilton tutors here, as will Dr Huber (when he returns from sabbatical), both of whom are excellent tutors.