I got this drive to replace the 160GB drive in my macbook pro. Backup and installation were all fine. The drive fit in perfectly, screws tightened without any 'nastiness', laptop started up without any glitches.
Performance is noticeably better. Program access times are faster and sites on my localhost seem to be pulled up quicker.
The only downside is this drive is definitely noisier than the original Hitachi one that came in the laptop. The original one was completely silent, whereas this one is merely quiet. More noise suggests less efficiency, which could mean less battery time (although I haven't tested this). It could also be due to the fact that this is 7200rpm versus the original, which was 5400rpm.
It's not a huge deal, but some people may notice the difference in noise more than others. Overall, and for the price, this seems to be a great product.