Pikey Dave's right - you get what you pay for with bearings. You can get non-euro spec / class 2 bearings and whilst they're cheap (usually half the price of OE), they're cheap for a reason. It's yet to happen, but one day I'm convinced I'll change a set that will still have 'Coca-Cola' on them...
Some bearings will have the OE name on them - if you look at the pic I posted in #17, you'll see 'ALKO' lasered in to the bearing, bottom left, at about 7 o'clock. Look out for this and you should be ok.