When the founders sold to Match, and presumably also got less involved in the day-to-day, suddenly I stopped hearing anything good about it anymore. I can't personally vouch for it, being out of the market at the time, but it went from being a pretty reliable recommendation that I'd often hear friends talking about, to quickly developing a reputation for having a high creep factor, lots of low-effort and fake profiles, etc.
As with many businesses, I think the demand for growth uber alles killed it. If they had been content being a niche service, they would have survived and served that niche well. But too few businesses (especially startups that get sold) are allowed to do that; their management requires they either shoot the moon or burn up trying.
In particular, I think there is a solid niche for an OKC-like dating site that actively rejects "mobile first" low-word-count design in favor of the desktop (check your messages when you get home, no "swiping" from the shitter, etc.), emphasizes profiles with lots of information and underlying data to construct matches on something other than photos, and basically serves a very literate demographic. Basically OKC circa 2004. Though today, a modern version would also need tools to aggressively block users that are abusive or just plain "creepy", because there's an Eternal September aspect to the Internet today that didn't really exist back then, that you'd need to combat -- spam-type adaptive filters would probably do the job ('is this spam' is a pretty vague question for a machine, so is 'is this creepy', but you could teach the filters over time given a good dataset and feedback mechanism).