I don't think it's as simple as one good and the other bad. I think it's down to who made them. I've had alloys on my MZ since 1993 and they are fine, probably because they were made using lead or depleted uranium or something. The alloys on my last new BMW had alloys made of some sort of cheese, they won't have lasted past the third set of tyres. My current Triumph has had none of the snapped spoke issues they are known for, but I bought a spare wheel on e-bay that promptly broke a pair. That rim was from a different supplier.
For £2.5K I'd stick with what I had unless they are known to be poor.