I was choosing between Crucial M4 256GB and Seagate XT 500GB. Crucial M4 is about 4 times as expensive, while offering about half the capacity. Or in cents per GB: Crucial M4: 136 cents per GB Seagate XT: 18 cents per GB (europe) Now here's how the Seagate XT performs in real life inside my MBP 2011: http://www.youtube.com/watch?v=HZLNGI6KP2Y If you watch the video you'll see my usage and why the XT performs nearly the same as an SSD. This is the reason I choose the Seagate XT. I am aware that the SSD has some other advantages (better shockproof, longer battery life) but the large premium over the XT isn't worth it in my opinion.