Hybrid drives are an interesting proposal, billed as the perfect blend of low cost space (HDD) and high speed cache (SSD), but the reality isn't as interesting.
The drive is 500gb, which is modest by today's standards but plentiful for a laptop drive. You only get 4gb of SSD cache, which is constantly being filled with your most used files and programs- in theory this means that your most used files will open quicker, and it would work if you used the same programs again and again, but for my usage pattern where i'm using lots of different programs it never gets to learn what I really need to be committed to SSD- and you have no way of controlling the space manually.
Despite this it's actually a very speedy drive, being 7200rpm rather than 5400rpm and having a hghly dense platter.
I have had zero issues with this drive, and it runs much quieter than my old drive, faster, and has twice the storage. The drive occasionally 'chirps', although this sounds bad it's actually nothing to worry about, and I think it might be isolated to the older macbook pro that I use the drive in.
Don't expect SSD like speed, but worth considering over a standard 500gb drive if you don't want to go for an SSD. Recommended
What is unique about the Seagate Momentus XT drive is that it uses both a traditional hard drive and a new-fangled Solid State Drive (SSD) to do its thing. Why? Large capacity hard drives are cheap but relatively slow when compared to their SSD counterparts, and unfortunately, for most people, large capacity SSD drives are currently prohibitively expensive. The Seagate aims to provide a third way - fast, high capacity drives for the budget conscious. Has it succeeded? Well, yeah!
I bought this drive to go in my late-2011 15" Macbook Pro, primarily to improve performance when using Logic Studio to make music. My previous hard drive was the stock 5400rpm drive that came with the Macbook and I had trouble with my music projects when they got beyond a certain size. I'm happy to report that I've not experienced any such problems since the upgrade, and have noticed several other improvements in general use.
The hard drive works by continually moving the most frequently used files to the faster, SSD portion of the drive. This means that the improvement to performance will largely depend on the computing habits of the user. Those who use the same applications every time they use their computer will notice the biggest improvement. I personally use my laptop for quite a wide variety of applications and so the performance of the drive is also fairly varied. Thats not to say that it is ever slow, just that applications that have been used recently, open a lot faster than those that haven't. For me, most of the time I have a hard drive that is fast enough for me to never think about how fast my hard drive is. Then occasionally, my hard drive is so fast that I notice how fast my hard drive is, and it is a pleasant surprise. An all-round, positive experience!
The only thing I would say is that unfortunately, it does not have some of the other benefits of SSDs. It is fairly quiet by most standards, but does a little hot and bothered when being used for gaming, video editing and other resource intensive stuff, although the performance in terms of speed and general snappiness remains very high.