What, in your opinion, defines "the best"? What are the criteria that are most important to your performing situation? That will help you find "the best". What works for me may not for you. Both are equally legitimate, but some idea of what works for you will give a better understanding to those who may be more knowledgeable about what to suggest to you...
Well I just wanted to know what people are using for cap in bottle tricks- get some views on the products out there. If I was to be more specific with regards to myself I would say something that is impromptu, using either a borrowed bottle or cap. I'm a student and I normally do my tricks in the student bar or during/inbetween lectures/seminars where I would normally have a plastic water bottle or coke bottle on me, so that it doesn't look odd me carrying a glass bottle around. I'm also head of fundraising/charity work/volunteering at the uni, so I normally do tricks when we are doing street collections, charity stalls etc where I sometimes carry a water bottle to drink from.
I quite often perform an impromptu cap in bottle at BBQ's (we love our BBQ's). Have done for years and i am sure this method has been published before. It is done with a beer bottle/cap and a mysterious force. I think that should be enough for you to work it out. You can literally pick up any beer bottle from the ground, or the trash bin if that's your thing.
As stated above 'best' is a relative term. For example if i said i was the best magician in the world ... you would probably roll your eyes in disgust and think to yourself ... what a tosser.
Once you find the method you like, try performing the 'age old' coin in bottle, then suppliment it with a 'coin out of bottle'.