Holy wrong forum section batman!
It basically depends how good your DSL service is, i.e. how close you are to an exchange. Virgin Media are leading the way in shafting the consumer it seems, but who's to say others won't follow, and cable is in theory the fastest connection as it's more likely to be rock solid and less subject to contention.
But if you can get a decent DSL service then Be are meant to be the best.