I've never seen a post that better summarized what happened to Google

Kagi seems to have a strong stance and commitment on monetization being solely through subscriptions and being user centric as a whole while You doesn't even seem to be able to commit to offering a path away from ads in your search results; instead just focusing specifically on being more privacy friendly. Based on the names I was almost expecting the inverse where You heavily promoted itself as the hyper user ("You") centric option in all aspects and Kagi to be the differentiated but still somewhat product focused offering.

I can't compare actual usefulness of each as Kagi is invite only at the moment but I will say You seems to have a ton of reflow and it can be hard to follow results. The reflow gets progressively less bouncy on load the smaller the screen is though and if you go down to the responsive/mobile layout size it works great. On a large desktop screen doing a search results in a bunch of pop in/out all over the page and even after it loads scrolling results in more pop in near the bottom bar. There are placeholders but because there are so many different types of visually different result containers which don't all have appropriately sized placeholders they just create more reflow than they save. Moving the mouse around the page causes everything to instantly start reacting and sometimes things like videos stop when you mouse off while other times they don't. The left bar's abrupt mouseover transition falls into this "suddenly reactive page" category as well as it shifts the entire page to the right the instant you hover it and the entire page goes back the instant you don't.

Overall it feels like getting the kitchen sink thrown at you as it loads results e.g. searching "picture of the mona lisa" gives 3 different inline picture streams and a music list in the first page results. The picture streams... alright, it's what the query was asking for even if it's a bit much to have 3 separate displays for it but I'm not sure why it feels the need to meet a "special display section" quota by displaying songs from Spotify. I'm guessing a lot of this goes away as you customize the site and do things like disable the "AI" but it's a hard sell to convince someone to put time and effort into figuring out if they can customizing something enough to their liking as part of their first impression.