i guess it depends what your priority is. Not having a car is no fun (ok, maybe if you're somewhere with good public transport, like a tube or something, but here in northern ireland, believe me, a car is a godsend), and if buying the engl screamer means you can't afford to drive, i'd probably go with the cheaper amp, lol.
However, if you think you can afford both (as long as you don't have to take out a loan or something, obviously), the screamer is, in my opinion, far superior to those two amps. It may even save you money in the long run, from the point of view of not having to upgrade as soon (or indeed, perhaps ever).
EDIT: if you're willing to go used, that laney vc50 could probably be snapped up for a similar price, if not cheaper, than the valveking or randall. That's what i'd do, if you could find one in good nick. Assuming you can't afford the screamer.