there are 3 hardware versions of the pny cs900, they are not really fast, or reliable. One of the worst SSD out there but cheap. 240GB model is build on Phison S11, the same as that gigabyte 120 GB SSD of yours. That controller have a design defect, that causes it to corrupt it's firmware, and go into the service mode (that "SATAFIRM S11"). It's a NO NO for me.
Very good rule when buying SSD, is but one that is build on the top model for that category of SSD, from big ssd controller manufacturer like phison, marvell, samsung, or Silicon Motion.
Crucial mx500 250GB, and a WD Blue 250GB 3D, are good choice. But they to can fail, just not are frequently as the cheaper SSD, but still.
And remember always make a backup.