Its a lot faster with a larger bombload and about the same range. It was also manouverable enough to be used as a nightfighter and flexible enough to carry guided bombs which were used effectively in combat.
The Welly was outdated as well... No. 311 Czechoslovak RAF Sqdn flew them, was very succesful but also had huge losses... slow, bad armour... In 1943 they were re-equipped with Liberators GR Mk.V.