Funny, I just ordered a 4 pack of cougar el-cheapo fans today for a little curiosity project I want to try out . . . http://ncix.com/products/?sku=81840&vpn=CFT12SB4&manufa... . I looked at the ones you linked too but since it was for a curiosity project I didn't care so much. No idea what their 'hyper-spin' bearing is . . . hopefully it doesn't make a hyper-annoying sound.
I tried to find that 4 pack, but it was gone everywhere when i went to order, so i had to get them individually, and ended up with nicer ones. The main difference is the 3 pin instead of 4 pin PWM, and the bearing is rated for 150000 hours (17 years of 24/7 use) instead of 300000 (34 years), other than that they're the same as the one's i linked, you should be very happy with them.