This something I have thought about quite a bit. And I will preface my comment by pointing out that I have not done the Brainwave Deck more than a couple times in a performing situation, so I don't have a practical basis for a fair comparison. However, I have done the ID forever, and it is just so incredibly strong, probably right up there with Card On Ceiling as the card trick that has consistently gotten me the best reactions.
My feeling is that the ID is stronger. Why? First of all, since there is one card face down among all the others when the deck is spread, there is there is that wonderful moment of drama. It is almost as if the effect first gets to play in their imagination - not unusual for their faces to light up in exquisite anticipation and to hear a "WTF" or "NFW" type comment exclaimed. Then when they take the card out, as you know, they are absolutely destroyed. You don't have this with the BW deck, it's face up immediately, kind of "Wham, bam, thank you Mam.""
Now, there is certainly the temptation to follow with the kicker: "And look, it's the only red card in the deck." But that could, in a way, be an anti-climax that blunts the impact of the powerful moment of astonishment they just experienced. I think I would rather just let that moment linger - and they will remember it and talk about it for the rest of their lives. Whereas, introducing the different color back may be overkill. And it may change the track of their state of mind from sheer and utter amazement to putting on their logical hats, leading them to stop and question, "Hmmm a different card - is that really an ordinary deck?" And with the ID I have literally never had anyone question the deck or ask to examine. So, as they say, "If ain't broke, don't fix it."
However, this discussion has me curious and, in fairness, I want to field test it by performing the BW deck and see how the reactions and feedback compare to the ID before coming back with a final verdict. After all, no matter what we might think, the audience is always the jury.
