There are two "Cheetahs".
The Mark I flavor is a near twin to the .22-243AI, sharing the 40 ° shoulder. The Cheetah Mark II has a 28 ° shoulder. Main difference is that the Cheetahs are built off necking down (small primer pocket) .308Palma brass. Whereas, the .22-243Win & AI are a simple step down of .243Win brass.
I had a .22-243Win for a few years, it opened my eyes to the capability of what a fast twist .224 hotrod can do. I could plaster my 1K steel target relative ease, courtesy of Alliant powders & 75 Amaxs.
Fast forward a couple years, compared my .22-243Win case side by side to a .22-243AI. That got the wheels turning on how to make a very good thing, better!
Side by side:
Cool thing about the .22-243Win is, there is brass, everywhere for it. Heck, I just picked up 50pcs. of Hornady at the local range, for free. Or, you can load with Lapua & roll in style.
For reloading, if you have .243Win dies already, you're either halfway home...or already there! A .243Win bushing die with proper bushing is all ya need for sizing. And, a .243Win seater will work fine for heavy .224 bullets.
Same rules apply for .22-243AI dies, all ya need is a 243AI bushing die. The 243AI seater works fine.
Middlested is a cool round, almost like a .22SLR. But, if I'm fireforming, I'll go 'full monty' and blow it all the way out to AI & enjoy the extra capacity. Beyond that, the Middlested is gonna need a custom die if you wish to FL size at all. Might get away with a .243AI sizer? For that, the net gain in performance is negligible over a .22-243Win. I have 'one off' wildcats & custom dies, but only because there wasn't an easy alternative. Simple fact is, a .22-243Win is just that...easy!
For easy peasy, throttle up a .22-243Win with RL-22 or 17. By the time you need to trim brass, it'll be toast. And ya won't fret losing one, here & there...
Or, fireform that .22-243Win to an AI. More capacity = ability to run a full case of slow burn powder like H1000 or Retumbo. Might just eek ya out a couple hundred more rounds on the back end, and you'll still hit that 35-3700fps 'sweet spot' where a 75-80gr bullet seems to perform optimally, without over-stressing the bullet...
Performance wise, whatever a .22Creed can do, a .22-243Win has already been doing for a long time. .22Creed is just the new kid on the block to reach the same end. If Lapua 6.5Creed (smal pocket) brass comes out, you'll need two steps to get to .224. Whereas, Lapua .243 brass is one step. Up to you, if you think the percieved benefit of (small pocket) Creed is worth the extra step?
.22x47L is a little badazz, but you'll need to pressure those cases to the roof to match a .22-243AI. And likely, that will negatively impact barrel life that is already short on a .224 hotrod. Up to you, if you consider that a good idea?
Wild card (for me) with the .22-243AI is using RL-26. I still haven't been able to find any! Bet that would make a .22-243AI even more of a short action monster than it already is...
Obviously, we've all got our favorites! If you've got components for any of 'em, that makes decisions easier. Regardless of what ya go with, you'll have ALOT of fun!!!