Define AIO coolers I really don't know.
If your talking air coolers then I would suggest Noctua as the best, 6 year warranty.
I bought 2 to replace the Intel stock cooler on my LGA 1366 motherboards.
I also bought 2 140 mm pmw fans which cost about $30 each with shipping, very silent.
The coolers dropped my temp on 1 motherboard about 20c and on the other 15c.

Yeah, I mean aio liquid coolers. I'm also delidding the 7700k using the RockitCool tool.

I bought the Corsair H100i v2 for my 6950X, worked well for that CPU.
Go to Frozen CPU.com for water cooled solutions.
Or https://koolance.com/
 

I would like to EVGA design expandable system.
Same as EKWB Predator. That would be awesome and demand for HydroCopper models would be bigger.
Combination of AIO for CPU and GPU block for GeForce to be 250-260$.
I'm sure EVGA could build nicer than Swiftech X220 Prestige.
Because that's one step below full custom loop and one step above AIO system.
For people who want to cooldown hardware overclocked max without extreme overlocking but no money 400-500$ for custom loop.
It could be done for 350 but without GPU block. But if price is 250-260 or 280$ with GPU Block that would be nice.
But last 3-4 years I didn't overclock hardware so high and normal AIO was enough. Except with i7-3770K, in that period I really need custom loop because I had stable 5.0GHz, only temperature was problems, with 20C lower temps I could reach that spot.
Now I would need watercooling for 4.5GHz on i7-5820K but I think that would not be some huge difference from 4.2 and maybe is better to think on X299. I want when many customers change to AM4 Intel to launch nice processor with better memory optimization, same or better performance than 1800X and much better memory write-read-copy results than AMD and I would upgrade on Intel.
And than when people compare 3200MHz DDR4 on X299 with 3200MHz on AM3 X370 difference will be huge and all SSD, M.2, extraction, unpacking, everything will work faster, faster.

I have really good experience with corsair, i have used this h100i for a few years now and it has worked quite well, but i am looking at changing to a newer setup, at least a 280 rad size, i really like the semi custom swiftech but the reviews forit are so-so, alot of leaking issues. so now im torn, do i go with a typical AIO, a kinda custom or for custom? so many choices  

Swiftech H320 X2 Prestige. 
 
I've had zero issues with my Swiftech H320 Compact Drive II.