When you choose your SSD, and you look at the benchmark, you have to know that syntetical test are maybe far from the real environment. If you look only at the sequential speed you are not able to appreciate how the SSD will really work, if you look at the random read and write speed you are closer to reality. If you are a multitasking user, you better choice a SSD with great IOPS. And sure the access time, the best SSD have normally 0,1ms.
Input Output Per Second: The IOPS performance tell us how many operation the drive can do in 1 second, if you are a multitasking user (for exemple you use to work with many opened windows at the same time like trading, Office, Web, Music, Antivirus, gaming, all together) and you buy an SSD with low IOPS performances you will risk to have long latence time between one task to another one, and maybe a crash, even if you have a Multitread CPU and a lot of RAM. If you buy an SSD with many IOPS you will be able to work in every multitasking and multiusers intensive environment.
A SSD with only 120 MB/s in sequential read speed in a real environment work much faster than another SSD who have 180MB/s in sequential read speed, if the first SSD have much more IOPS.
If you work in a multiusers environment, a server, you have to look especially to the IOPS, many IOPS means that the SSD can manage many users request. If you buy an SSD with low IOPS the risk is a bottleneck when many users will connect to the server in the same time.
For the security of the data is important that your drive have a controller who can operate the ECC (Error Correcting Code), normally the best SSD have an ability to rectify errors with a rendering to <10(-14). The best SSD have actually also an UPS-like system in the drive who can guarantee that all the data in the cache will be written in the drive even in case of power drop.
For the longevity of the SSD is important that the drive have a wear-leveling algorithm mechanism, the best SSD have now 3 layer wear-leveling, dynamic, static and activ, with the actual best write endurance of 100GB/day for 150 years.
The most important performances to check are the access time, the random performances and the IOPS.
For the lifetime the most important feature is a good wear leveling system.
For security of your data the most important is an high ECC (Error Correcting Code).