I will agree that a fast pit man is a great asset but I still think that a fuel gun will be faster than a bottle. You will be 99% sure that you are full with a gun where with a bottle, your pit man might not get you completely full.
As far as what gun is the best, I would have to say the RB gun. I have one and it has not leaked on me yet. I have owned it for about 2 years now. I have had the dynamite and proline ones and they both leaked within a month.