Two similar effects (achieved via two very different methods): a two-deck “one card across” plot where a selected card vanishes from its own deck, and reappears within another deck of a contrasting back color.

For those familiar with both, I’d be most interested in hearing your thoughts in comparing the two, regarding their relative strengths or weaknesses relative to each other. Do you have a preference among them? If so, why?

(Or any other thoughts you might care to share relating to either or both of them.)

I liked Bob's trick from years ago. I'm pretty sure I still have the booklet here, I think it required glue dots (which a few magicians were using for different effects). Thinking there are so many options now besides the glue dots which I don't think are made anymore. Not familiar with David's effect.