The Yeti sizing is a bit odd which is why I went for a medium ASR5 (I’m 6′; Yeti suggest a Large if you’re more than 5’10). I guess it depends what you want to do with it – it’s quite a versatile frame. If I was doing a lightweight race-ish build with 120 forks, then the large might have made more sense.
The ASR5 is less travel but slacker and stiffer than your 575.
I know they get a lot of great reviews, but I strongly believe the ASR5 is not for everyone. It basically forces you to be pinned all the time, and the suspension is fairly firm. For general riding this might come across as harsh and unrefined. You’re forced to pick lines better, and it’ll punish you for straying from your intended path. It’s not until you start going quickly it all makes sense – It’s a really stable platform and great for chucking around since it doesn’t wallow in its travel. I love mine but I’m sure there will be people who (if they’re honest with themselves) hate it.
I haven’t ridden a carbon ASR5 but I understand it feels very similar to the alu one, and the £600 price difference is hard to justify for 0.5lbs weight IMO, better to spend that on some wheels. Depends if you’re someone who needs to have the best, I guess.
The Mach 5.7 is a bit of a different beast. It’s got 25mm more travel, for starters.