I need to upgrade Asus X455LDB disk, what would you suggest, considering following requirements for the SSD
by the way,Is there any difference in life time or performance in 256GB and 512GB?
Crucial MX500 500GB
This is about the best SATA SSD series that I know of, they are not very expensive and are availible from 1/4 TB to 4TB. With your budget, 500GB is probably the best option.
I'm getting a little off-topic here, but if you want to transfer your files, I reccommend booting from an Ubuntu live ISO (on a USB stick or DVD) and using dd to transfer your files, and Disks to resize the partition so your OS (Linux, Hackintosh or Windows) sees the extra free space. (and for the diamond mods, I include this so there is not an off-topic question about transferring your OS that I have to close)
About the durability, the larger the SSD, generally it can also be used longer, because you can write more to it since you have more NAND cells you can write to. Although each NAND cell can only be written to about 360 times, with a larger SSD you have more of them so they wear down less quickly (or you write more to your SSD, but don't do that too much)
