This is a very weird poll, there are tons of dice sites around here and you cant just compare two sites and also what weirder would be that you are putting bustabit in the poll , although the site is nice but thats not a dice sites. Apart from that the word " best " is pretty much ambigious because there are alot of criteria of each dice sites that distinguish them in term of the word "best" i.e PrimeDice is definitely not the best in term of roll speed and as well as "speed" of their support service

A poll like this is pretty much not needed because this kinda thread has exist alot

For references :

https://bitcointalk.org/index.php?topic=1139574.0

https://bitcointalk.org/index.php?topic=999550.0

https://bitcointalk.org/index.php?topic=927445.0