My greatest frustrations with Fet Life ( and yes, it's a fetish site, hence the name. It's not only about BDSM. ), is the overabundance of females solely interested in peddling their sexual content via Only Fans, and the fact that, for those males seeking females or couples for dating or play, their Search Feature has no filter to weed out all the other male profiles. For the latter, you basically have to scan through long lists of members with whom you share zero interest, and there are far too many guys there. For the former issue, those folks, mostly college-age girls, are mainly about providing masturbation fantasies, and getting paid for their services.
My greatest frustration with Adult FriendFinder, Swing Lifestyle, and SDC is all the bots and fake profiles. At least with Lifestyle Lounge, their use of a Real Seal system helps identify the genuine profiles. However, that site is in serious decline, with minimal activity. What activity found in their Forum is reduced to cliques who attack each other over political biases, and a strong hatred of Single Males.
Another gripe I have with AFF is the unnecessary clutter of their site design. They try to accommodate "vanilla" dating as well as swingers. Their lifestyle groups section is separated from the dating section, making it difficult to reach out to members based on their profile links when you share a common kink. There are far too many features to navigate and keep track of, and they've adopted the modern system of accruing points. These points build up based on your site activity, or you can purchase them to gain certain advantages in contacting those members who interest you. So, it's not enough that you have a paid membership, they want to get even more from your wallet by further making you compete for attention.