Really? ...
Do you have the links to the faster ones?
The groundwork was laid a long time ago.
https://github.com/Telariust/VanitySearch-bitcrackFaster, with multi gpu support. Take existing code and make the tweaks one wants/needs. Much easier to understand and tweak vs bitcrack, IMO. Pool operator can verify that it is faster as well. It also supports the newer cards, 30xx series.
Ah Yes ...
I have seen this. Never looked too far into it or used it though. A lot of forks out there

Pools are great in such a space as this, but the issue is that unless code is available for dissemination and Fine Tooth Combing, then it is difficult to 'assume' that the owners of pool are honest and equitable. Trust required. The complete opposit of what Crypto was but for in the first place

Which pool are you looking at/working with?
#crysx