There are several background operations that happen on ssds, low or high end doesn't matter they all need them. I've seen quite a few supposedly high-end ssds that show abysmal behavior with wide variations in performance across time.

SSD qualification is a tedious job.

It's not even just about performance of the SSD the other points to care about are non-trivial if you intend to use lots of SSDs for important tasks. I collected some questions to consider at http://disksurvey.org/blog/2012/11/26/considerations-when-ch...