I've currently got a 40 psi/ninj stalker.
Caltrops is a little disappointing, but it can cause enemies to run away, if you're single target focused like I am that's a good thing, as it lets you concentrate on one while the others attack less. It could be useful solo for mitigation, but it's pretty useless in a team, and there's the next couple powers for mitigation.
What I'm really disappointed with is Blinding Powder, the sleep is so short - only 5 seconds, it's not really enough to do much of anything, the confuse is the same length of time and usually only gets one or two targets usually, the cone feels really narrow, and I'm not sure what good it does having the mobs both asleep and confused. I've read possibly slotting it with contagious confusion could be useful. I'd also consider instead slotting it for sleep duration, it might be enough to matter for sleep if it's 10 seconds long, that might be enough to kill two or three mobs in quick succession solo. I feel like I'm missing something I can do with the power. This seems like this is another useless on a team power, but I love my confuses, so I might stick with it and see if I can figure out something to do with.
I didn't take the Smoke Bomb, the idea of an area effect placate sounds awesome, but apparently it isn't a real placate, I've read it won't put you into hide, so you can't auto crit against the placated mobs - it may be an alternative to blinding powder, or allow you to run away to live another day.
My favorite part of the set is the pretty big heal. Slotted with some recharge and heal, it's usually up if you need it, and if it isn't you can run away and usually get it off shortly thereafter in time to save your skin.
All that taken, it's probably a much better solo set than any other available.