Carib Sea Live Plant Substrate

My LFS recently began stocking a new substrate product "Carb Sea Live Plant
Substrate". Neither the owner of the store nor the employees know much about
the stuff. They haven't stocked it long enough to get much feedback on it.
Anyone here ever use it? Does it work well as a substrate for a live plant
tank? Does the fact that it is packed in water have any real effect on the
time it takes to cycle a tank? Do the plants grow well in it? Should
anything be added to it? (Laterite for example?)

Just curious what others experience is before I sink any money into it.

Doug