I have an x24 and have no complaints. It's super loud and sounds good.
I think the biggest issue with them is moisture, they do not like it. Other than that and guys just blowing the speaker from turning it up too loud I don't think the x24 is known to have that many issues. I do know that right now it seems like on social media and forums that the x24 is the most popular call ten fold over everything else. One of the main reasons I went with it is because of the MFK library.
From what I have read whenever this question is asked most people say that the x24 is louder.
If you want a call that throws the sound in all different directions then the x24 is definitely not the call you want. Due to it basically being a horn it is very directional. With that said, it is loud enough that I have no issue calling in coyotes and cats 90 degrees from where the call is pointed.
If you want better quality sound, look at Lucky Duck.