Personally I would use Sandman's Pouch over Grandiose Power trinket. Track the proc and align your CD's. Also it procs fairly reliably on the pull, which makes it far superior (imo) due to the stacking effect it can have with pre-pots/lust.
The proc itself has ~17% uptime, which in a vacuum breaks down to ~243 Crit per second. So your trading 8 int for 60 crit..... If only it was that simple to math it out. To truly find out you would need to sim it.
Personally I'm 90% confident that the DMC trink will come out ahead.