This isn't something you can research to prove. Its not numerical data and therefore it can't be proven. You may very will be the best but I choose to believe that you are not and that its more likely that one of the first generation speed one alliances are.
If you guys every go and win in every server, against every alliance ever, in every different setting that exists, and have not one of the alliances you verse loses a good member to the real world, then and only then can you say with absolute certainty you guys are the best alliance.
Oh and all those alliances you verse have to have guys that have enough time to play. The translation of this is you can't prove your the best, you're likely not the best, and its extremely arrogant to believe that you are.
That said you are the best alliance in this world and you should be satisfied with that.