Personally I don't have much to complain about with the Steam Recording feature. It does all the work in the background as I play, then I'm left with a sequence of game footage afterwards I can extract clips from trivially from the client.

Plus you can export these clips in accordance to what file size you ultimately want, which is very convenient as it will compress the footage as much as necessary, and conserves the quality fairly well. Good for quickly posting on discord without a subscription for example.

The drawback is that I don't think you get very many special effects and transitions with Steam Recording, unlike OBS which has a big toolbox of that stuff. Also, the options for recording audio from different sources is kind of limited with Steam Recording. There are a few options but it's usually either record only the game audio or record the audio of everything.

Another downside is that depending on the game, the Steam Recording can just straight up fail to record at certain points, like when you first resume from the main menu, but this is usually only prominent with older games. I doubt that Elden Ring has this issue, for instance.