I've been using SuperThrive for my seedlings all spring, and I think it's made a difference, most are ahead of last year.
In the garden last fall I divided and moved a huge number of plants using Root Blast. Nearly everything survived, and many things filled out quite a bit. The biggest surprise was a white polycodon which had been in a pot and looked dead. I stuck it in the ground anyway, just in case, and made sure I put a marker in the spot. Last weekend it was up several inches!
A local nursery swears by Biotone...
I see there are rooting stimulators everywhere now... Is there a way to tell the difference between them?