I used to be an all Hollywood player, then dabbled a bit with brawler, but for the last week I've been maining spec ops and you can def tell the difference in certain match ups.
Chars I really like Hollywood for:
Scorpion, Quan chi, sub zero, takeda (cyro and unbreakable only)
Generally I like Hollywood for chars I want to stay close too, that have slow normals, or can get out of spec ops corner shenanigans easily. Scorpions teleport can get out of the corner fairly easy from my testing, I love the standing reset against Quan cause his normals are all slower then mine, and sub can also get out of the corner with his slide.
Chars I really like spec ops for:
Erron Black, tremor, raiden, kenshi, mileena, grandmaster sub
I like spec ops for chars with slow wake ups that basically just have to hold that in the corner with missiles coming down. I also like it for kenshi, because Cassie still keeps her quick normals, so if you land one hit on kenshi, you can call in ex missle to make it easier to close the distance. Also in the sub match up, missiles are just another tool that helps Cassie deal with clone.
While I do think brawler can be every bit as good as Hollywood, brawler is inherently more risky, and I can't think of too many situations where brawlers additional tools make up for the lack of spec ops corner game or hollywoods standing reset/vortex, but I'm open to other ways of thinking.
I'm by no means a pro or have as much exp as some others here, but it seemed this thread didn't get any traction, so maybe this can start some discussion, and just wanted to share my thoughts. I think this is good discussion for us to have as Cassie mains, with us having 3 viable variations.