one word: COMPLICATED! i read Anand's comment today. the western digital guys say they asked the customers and they said that they want control over what happens. i say this is false and taken out of context. cons: - you see the ssd part and after a windows driver install you see the rest of 1TB... i don't care much about linux and consoles (i'm a windows/android guy) but this extra step makes it complicated and limited. - you have two drives that you have to be conscious of. for regular folks using one normal drive is complicated as it is. - both drives are accesed through same port so simultaneos usage will impact performance. - the ssd controller is at most mediocre - the price is rather high to consider using this pros: - a single physical enclosure and a single port needed - it's manageable for someone that has a little know-how what i think makes sense: - single enclosure - transparent caching that gets good performance. seagate kinda got it but the amount of cache is too low and the price is too high. i am a geek and still i do not want to mess with two drives to look like one. it's more convenient to have the caching side transparent and not have to have special drivers, configuration, mantainance etc. the extra driver needed does not seem as a big deal but it is. i want the drive to be seen as a single drive and not have to mess with it besides connecting it, partitioning it, using it. - they drive has to work out of the box. it's ok if i have some control over the caching. don't mind if config is limited or absent. but i has to work out of the box! - either seagate solution with reasonable amount of cache, at least 32gb, maybe 64 or 128. probably 64gb is the sweetspoot now. - eiter use a ssd as a cache like intel does. maybe microsoft will implement this so we could use one/several ssd(s) as cache for one/many mechanical drives. using one ssd as cache for one/many disks would be good enough. - we have to have write caching also! reading is done usually once and windows does a good job caching reads. caching the writes is done too conservative in some scenarios. - great price per gb of space usable. seagate made some good steps but not enough. - wd solution simply is niche and needlesly complicated and limited, making it ok in few scenarios but a bad overall solution.