> Provided you don't hit AMT
I think people downplay how easy it is to hit AMT. A single, no dependents, standard deduction filer making $120k will hit AMT after $26k of on paper gain for ISO exercise. Everything after that will be taxable. Filing jointly, 2 people who each earn $120k can absorb $18k in on paper gains from exercising ISOs. Add in a kid and it drops to $15k.
That's a paltry sum, basically breaking any advantage ISOs provide.