The hotend holder im using is a slightly modified version of this from jcenhttps://www.thingiverse.com/thing:2420635
The X carriage bearing holder will mount up to the stock hotend holder also. It uses the same 4 pin and a screw mounting system.
Im not sure there is any advantage to one of the other. I just don't like using the brass inserts. I found my hotend was a bit to close to the fan duct and it eventually melted a bit. it might be a goof idea to wrap a bit of kapton tape around the end of it....just an idea. I mostly print stuff with out a fan so i have not bothered working on that... Also I switched to a volcano heat block so my fan duct is currently the wrong length. I have some various fan ducts on my other hotend carriages in my things that mount the same but i think i made longer for the volcano. Sorry for the long winded reply.