It should be noted that the SanDisk Ultra II series is less stable then the SSD PLUS, because of the MLC and TLC technology. (They use Multi Layer Cells - so they are cheaper to produce, and less stable) I'm not saying that they will crash, but it may be worth spending a couple of extra bucks on the SSD Plus for the same drive capacity.
EDIT: After doing a bit of research, SanDisk has implemented caching technology in the Ultra II to make up for this (partially)