I rate SAM/NIN about the same as a full time Domaru SAM for EXP parties. Personally I have never unlocked NIN.
Gimp your damage that much and you don't need shadows. You will never pull hate against me and I am neither fully merited nor dressed in uber gear.
don't /NIN, don't full-time hasso or seigan. keep hasso up as much as possible and put seigen up when you're in trouble or about to be in trouble.
Quoted for truth.
Hint: While under Seigan, you can hit 3rd Eye, then immediately swap to Hasso. Your 3rd Eye recast remains at 30 seconds.
My only problem with the Hasso / Seigan dance is hitting my Seigan / 3rd Eye macro too soon after a WS and not getting Seigan activation. This leaves me in Hasso with 3rd Eye on a 1 min. recast.