Im deciding between a velociRaptor 10k RPM or Raid 1 of 2 hdds. (I dont like Raid 0 b/c of the double risk of dataloss)

Anyways, will the "Read" on Raid 1 really be 2x faster than a single drive? I have read many forums and they say Raid 1 has very little performance improvement compared to a Single drive.

Does anyone have any respectable resources that states how fast the Raid 1 will run compared to a single 7200rpm or a 10k raptor?