I've seen the first two and a half episodes, and I have to agree with the consensus — it's pretty fun. Not always gripping in the way it thinks it is. But certainly enjoyable.
It's worth checking out for John Travolta alone. He's giving us this weird alternate version of Robert Shapiro that might actually reveal some essential truth about the man. I'm sure it will become even more fascinating as I continue to watch.
The rest of the casting is completely bonkers.
David Schwimmer as Robert Kardashian is perhaps the apex of the show's absurdity. He plays Kardashian as OJ's dopey, gullible sidekick, with a hopeless, unending, and possibly unconditional love for his friend. I'm skeptical that RK ever possessed the amount of boundless humanity that Schwimmer imbues him with. Which is not even to say that it's a good performance. It's just... weird.
Sarah Paulson as Marcia Clark doesn't really make sense, either. She appears to be a 27-year-old woman who is divorced with two kids and is also a veteran prosecutor. Paulson is actually 41, but she looks 30 at most, and she has absolutely no gravity. She tries to emote world-weariness and authority, but they are paper-thin impressions.
Cuba Gooding Jr., is, of course, a ridiculous choice for the lead. He has decided to reimagine O.J. Simpson as a whiny, confused buffoon. None of OJ's primary qualities come through. You don't get a sense of how physically threatening and rageful the man was. Cuba Gooding appears to be only a threat to himself.