But everything depend on the users, they use bitcoin mixing services that give them comfort except realible.
Personality i used [banned mixer] if i have got profit from gambling.
Cryptomixer is old and good, very similar of bitmixer with it's template and functions, they also proved here that they really own 2000 bitcoin reserve. Also can say that bitblender is good option and personally I trust them. Chipmixer is new but has some good and unique options + run signature and I guess they aren't scammers.
P.S don't forget bitmixcoin, they have 10btc in escrow and escrower is zazarb, so it guarantees safety.
With regards to how good bitcoin mixing is, well bitmixer already was closed and I haven't heard any good rather than the new one whose chipmixer right now it did have great profit and their campaigns was doing great. I don't prefer to talk about those other mixers, because the mindset I have is on those actively having campaigns and that's the assurance for us of trusted mixing services.