For example, the Intel 520 and 530 series have known issues. Besides the lower performance after some amount of writes, they also tend to randomly "disappear" from the system, which is much worse.
Google it, it should be easy to find many related topics.
I don't know if this only affects the SATA SSDs or not, but it happens a lot. (BTW, the random disappearing also affects some other SSDs from other brands.)
The Intel SSD 520 and 530 use SandForce controllers, so Intel started with a big mess and spent months trying to clean it up before shipping the drives. Clearly they missed a few bugs, and they couldn't work around every mistake and design limitation in the controller's hardware.
Intel's in-house designs have an extremely good track record. I'm only aware of two major bugs.
I don't know if this only affects the SATA SSDs or not, but it happens a lot. (BTW, the random disappearing also affects some other SSDs from other brands.)