If I did not tary to praise the previous model, you had to be on a capacity of at least 480Go to have good performance in everyday life. I am forced to observe that holds well Crucial promises announced MX with this range and even in small capacities (256GB = 240GB once formatted). The improvement is significant compared to the preceding models (M4 / M500), at least for the 256 and especially 512 GB models (which I buy for my personal use soon to replace my M500 / 480Go which always makes me proud candle). When I run a PC or Mac, even with a HDD 7200 / 10000rpm, what sacred flashback that time, lost productivity. Why these same manufacturers are still struggling to sell bikes without SSD. It's like installing electricity at home and then riding a bicycle to supply power to the entire household ... I can only recommend it and my family and to you who are reading this: if there is indeed a computing device that is not a gadget and is ABSOLUTELY ESSENTIAL that is one, the transfiguration of your computer is on your doorstep! What do you expect him to let up (when I tell you that I ignite myself product ;-) The value for money helps to pay for a 512GB model for the price of a 240GB of there just 18 months and the buggers they are fast and more (up to 550MB read / write 500 MB for the 512GB model) ! We are waiting for manufacturers to integrate a decent PC interface velocity of these discs and reach the GB / sec as is already present on the MacBook Pro and iMac 2013/2014, through the pci-express by example. To clone the system drive (often delivered in 5400rpm on laptops, sic :-( I use preferably the free EASEUS Todo Backup Free enables you to copy all partitions including those manufacturers that are hidden, allowing optimize it for that it what is SSD, but also resize (before cloning) destination partitions to the desired size. Crucial, even if they allow you to download the same type software, it seems less "flexible" in its use. The little extra that really allow this brand to distinguish itself is to provide a "control center" of the SSD software, like Samsung Magician, SSD Tweak (free), which would manage the daily optimization, updates and integrity. They work according to information gleaned on the net ... The M550 the same manufacturer, to my mind, is only useful if it is imperative to have a capacity in excess of 512GB or specific formats like mSATA. These are my friends who are delighted when I installed them this type of hard drive that really changes the daily life of any user PC / Mac even on configurations there several years. Do not hesitate to take the plunge, you will certainly not regret it and your wallet will thank you!