Normalview...I get it now (I think)...repped you. Thanks.

Say I have someone with power Cosmic and Steath(could happen in a scenario) power Cosmic says powers cannot be countered so they would keep steath after Ambush right?

Correct.

Just keep in mind that "Counter", "Cancel", and "Ignore" are three very different terms in Heroclix. For example, Power Cosmic does not prevent Psychic Blast from being used on the character, since Psychic Blast is Penetrating Damage and Penetrating Damage ignores damage reducers (it does not counter them).

Currently Outwit and Ambush are the only two things I can think of that counter powers.

the ambush/ knockdown thing works better if you use it on a guy with stunning blow.

Vet AW Psylocke, for example. You want to make sure the first attack hits, so you ambush stunningblow with her. This is a 12 AV attack that hits someone for 3 and puts a token on them. Now she can follow up with knockdown and an 8 attack. Most guy's defense values go down after taking 3 clicks, so you have a better chance of that 8 hitting. Plus, your stealth is already countered for your pcer.

It's a good point, but I just wanted to counteract that boost to the defense that they get...I'm not concerned about Antman being a primary attacker (at least not in the scenario in which I plan to use him)

You could do that but now that some figures are fairly consistent and might have mid to late dial spikes, having a 10 AV for the first attack then follow up with a 12 AV versus the opposing +2 DV is equally as valid.

I used this technique with phenomenal success on the AW Vet Psylocke against an alt F4 team, but with perplex and ambush i was attacking with a 13 a/v doing three damage + incap or using the knockdown combo for two 10 a/vs.