I just got done cloning hard drive to external drive, installed OS X and it is unfortunately too late to reinstall the backup. I have the aluminum macbook 2.4 with 4gb ram and everything definitely is zippier, but not so sure about the vibration. Hard to describe what everyone is referring to in other posts when I searched, but I feel what I can describe best as a low humming. The drive is quiet (same as the stock drive) and not making any noise. But I am feeling what I can describe best almost the same as the fan running high on any laptop without any associated noise though. I am just feeling this on wrist wrest/trackpad. Is this the vibration people are referring to? The way I was reading into their descriptions was the drive was noisy and tons of vibration (like the computer was shaking ) or it was completely silent and they did not feel anything at all. Is what I am noticing normal for this drive? Should it be silent without feeling anything? I bought it best buy for $127 so that I could easily return it if I was not happy with it. It is hard to say if I going to keep it or not after just using it for 15 minutes, but the faster speed and larger capacity from the 250 is nice. I was on the fence about the 500gb 5400 or this drive, but I got this one since I just purchased the elgato eye tv from the Apple store last night and was hoping the faster drive would work better with video recording. I have 1tb NAS, so space was not a huge deal for me. Please let me know if my thought process is off base and should have used the 500gb 5400 drive. By the way, the eye TV at the Apple store was selling for $149 and I got them to match the price of $119 from the manufacturer website. Not a bad deal!