Got this in my email today, surprised that it is not posted yet. Occasionally they will do a 50% off storewide deal (eg 25/03/2014) so if you can wait then by all means wait but if you need something now then use this to get a discount.
Please note that standard delivery if free for orders over $50, which sweetens the deal. Use the code at checkout to get the deal.
Oh, and if all you want is a few things like business cards, magnets, postcards etc then "this is not the deal you are looking for". You may be better off just waiting to get those products for free and paying delivery with other vistaprint deals….they come along every 1743 nano seconds
EDIT: UP TO 40% off. However, this is a better deal than the last UP TO 50% off deal because many things were not discounted at all and if they were the discount was quite small - even still, this deal is good if you need to print now and can't wait for a better deal