Well it will obviously vary due to the intake, but i know Durham usually field a good crew, my bro did that Doxbridge thing and said Durham was toe to toe with Oxbridge in most things.
But as i said, my rugby team was absolutely awesome for like 4 seasons, but now the oldest year group have all gone to university its suddenly not as good. Things can change dramatically in short spaces of time. But then again, places like Oxbridge are obviously going to have permanent things like good infastructure and resources.