The only real difference between Bitcoin's (and LTC's, BCH's, etc) coinjoin and Dash's to my knowledge is a question of trust.

Dash provides a decentralized version of coinjoin where the user doesn't have to hand their coins over and hope they get them back. Dash provides up to 16 rounds of mixing. Since Bitcoin's solutions are centralized, I doubt they really have a mixing limitation. They can pretty much do what they want and they likely have more inputs to mix with.

In practice and if done properly I doubt someone can trace either Bitcoin or Dash transactions once mixed and after the fact.

I've seen many claims that it's been broken but followed by no proof. Perhaps if a transaction (either from Dash or Bitcoin) can be de-anonymyzed and it isn't the result of an obvious user error I'd change my mind.

Now regarding Monero trolling... I'm one of those people who can't seem to pick just one coin. However, it was specifically because of the heavy XMR trolling/hate on multiple threads that I avoided XMR altogether. Of course I regret that, because it's different tech and it does offer something useful to the crypto world. I don't believe a crypto can be true money without privacy. theymos and other BTC maximalists love the XMR crew as they always played buddy-buddy with big brother BTC while praising its superiority all the while attacking all other alts. Charlie Lee and LTC largely played the same game. Dash in contrast went right at BTC and has suffered quite the backlash over the years.

Still though, I can't see any one of these 3, LTC, XMR or DASH just going away. They've all established a decent enough network effect and are all in bull markets vs USD and are all poised for an easy 7x when the time is right. It'll likely be quick, one first, within a 2 week period sometime in the coming months, then the others will follow.