I am going to review this on the basis of 3 categories:
Method- This is the first cap in bottle effect that I have purchased so I cannot compare it to others. The method it self is quite in ingenious. It calls for very little to set up, which allows it to be virtually impromptu. Though you cannot just grap someones bottle and do it right there. Also it does require special bottles to do the more "improtu" version of it. On the forums users have created alternative handlings that work better but are less impromptu. It will require some practice to get it just right (as with most magic) so be prepared. Also it does take guts to perform this it does require some slight of hand. One final plus is that you can hand out the bottle for inspection), though you do not end clean.
Instructions- When you dl it you get a 2-3 page instruction pdf with pics and text describing how to do it. The doc its a little short and doesn't go into too much depth. The creator is supposed to be coming out with a video soon, which i'm sure will help clear up alot.
Practicality- If you were to preform this at a school it would be relatively easy to aquire acess of a gatorade or plastic snapple bottle. Though if you were to preform it in school you have to be careful of your angles. In all I might perfrom this from time to time. The few times I did perform this the specs had great reactions though which is a plus.
Conclusion- Overall this is a great, cheap cap in bottle that if you do not have one, or are looking for one which you end clean, this is the one you should get.