I like it. It is a good effect and will fool most laymen. It is quick, attention grabbing and has a good conculsion. I like the fact that it is very angle proof and so can be done with a small crowd around you, so it is good for pubs/clubs/restaurants.
The coin vanish needs work. The French drop is the best choice if you are standing (as it is very angle proof). If you want something easier, sit at a table and just lap it.
It is always good to have a good patter for a trick, but I don't think that this one really needs it. In fact, I would be inclinded to do it mute and rely on mime to communicate that I want the audience to do (I am assuming you get someone to initial the coin). I do a lot of work in noisy environments and so can not always be heard very well if there are more than 2/3 people. This is a good thick for getting a group's attention, but I wouldn't want to be shouting.
Finally, I would think about getting yourself clean at the end. After the coin drops into the cup, perhaps pick up the pack and put it in your pocket
Well done for putting this together.