I like misled a lot better. The pen is easier to figure out, but there is nothing to figure out with the pencil, since you can borrow it. I had misled awhile ago (I reordered it and now I'm waiting for it to come) and I have the stealth pen, and I feel I get better reactions with misled.
Mislead is my choice. My wife and I were visiting my family over Thanksgiving and I showed my B2 bomber to my father (we always discuss illusions... he's no magician, but he is about as smart as they come in terms of non-practitioners)...
anyhow... I showed him my pen through dollar and his first reaction was...
"That's not nearly as convincing as that pencil one that you do."
I think he is right. The pen-through effects are very limiting... whereas the mislead gimmick allows you to shove that whole pencil through the bill, wiggle it around, move it in and out... and show where the pencil is going in and coming out. Considering the issue of borrowing the pencil... I don't... but I do give the pencil away (therefore beating the situation involving... 'here, use my bright neon green pencil!')
I have also made a number of mislead gimmicks for bic and papermate pens... so I use these sometimes, performing the mislead effect.