I don't know if it will be cheaper, but it will definitely be handled with care. I have limited experience ordering from Amazon.uk and Zavvi, but since both are located in the UK, you have that chance your stuff is gonna arrive jacked up or damaged. Diabolik is based out of Philly and they package everything really nice. Really good customer service. They don't always carry Region B stuff you want, but they try.
I preordered Cujo from Amazon.uk. I've never ordered from any of the other two vendors before. I live in the US so, if I can get it cheaper from another vendor, i'll definitely go with one of them.
Hey, don't mean to message out of the blue, but just curious were you pre-orded the Cujo LE set from. Zavvi? I'm not sure what side of the pond you live on, but if you are here in the US, DiabolikDVD is going to have these up for pre-order as well. They are waiting for more info from Eureka. Just some FYI, because I am definitely getting this as well!