the pluses;
is it is very reliable
it is far faster then any hdd.
the minuses are;
it is costly
it is small
it is not as fast as sata III ,but sata III have not been shown to be as reliable as the toshibia II in the iMac is.
And as a complete aside if t-bolt boots how about an external ssd. like the one in this set of photos. The is a lacie attached via fw800 with 4 partitions , but if t-bolt works it is easy to see you can hide an enclosure. I just put that up in the time it took to write this reply and you can not see it from normal view spots.