For me I like Unstoppable unless my build is so tight that I need another Power. Then it goes. Do I miss it when its gone? Sure...sometimes.
My tactics for using it are something like this: Get into trouble. Hit Dull Pain. Hit Unstoppable. DP lasts 120 seconds, Unstop 180 (longer than the soft-crash T9s btw). Once DP drops I know that I have less than a minute to set up for the crash. I have a macro that announces to the team that Unstop is about to crash so I don't have to worry about them saying 'Hey where you going?' as I bolt out of the action.
Btw I have DP's Recharge at 185 seconds on my Brute so after the crash I pop some blues, hit DP and start the lengthy process of turning all my toggles back on. It takes longer to do this last part than anything else.
Personally I'd use the power more if it had a 90% crash instead of toggle-dropping. I could survive the former but seldom the latter and if I'm tanking running away from the fight seems like a bad idea for my team.
"Comics, you're not a Mastermind...you're an Overlord!"
Uber Talgrim - level 50 emp/dark defender
Uber Rod - level 50 dark melee/regen scrapper
Rod Valdr - level 50 invuln/SS tanker
Talgrim - level 50 ninja/dark mastermind
OMG!! Please add these costume designs now!