Looking at a Yeti ASR. Med is up to 5' 11", large starts there and that is my height. I have always ridden large frames but curious what the advantage of each size is and if there is any reason to go with the medium.

Depends on how it fits you, of course. Many riders seem to prefer a somewhat smaller bike for the additional control - so I'd begin with the medium as the more likely fit. But as we know, fit and feel is very subjective so throw a leg over and try them out. Don't worry about someone else's opinion of which you should have.

I have a 2015 Yeti ASR-c. I'm 5'10" and went with medium, I some times wish I had a bit longer top tube -I.e gotten a large. If you are taller than me I'd recommend the large.

Other than size you have any other comments on the ASR in general?

Smaller frame will allow longer dropper and a lower cockpit. The larger frame will let you sit down in the bike more, with a longer top tube and shorter stem. I'm 6' with a M Yeti 575, and probably should be on a large. I've got a relatively long torso, so I still need to run an ~80mm to keep the front end down.

Part of it depends on your build, if you've got a shorter torso, go medium, long torso go large.

Sounds like sticking with a large is the way to go, I have a lanky frame with long arms. Buying anything with long sleeves is a PITA. Settled on the ASR because it has more travel than my 2011 Jet 9, weighs less and is geared lower, which, with turning 60 a month away I could use the lower gearing on some of the tougher climbs.

My ASR is my favorite of all time, you'll love it. I am 5' 7" with a 30" inseam and I got a medium. It's just a touch big for me, just the way I like it.

I'm 5'8 on a size medium SB-95 -- It's very comfortable with the customary for our time 50c stem and 780 bars. I use flat bars as the front end is pretty high (but it's a 150mm travel 29'er after all).

Point I'm getting at is I was somewhat between the S and M in ideal sizing but the medium is working great

Really fun bike, geometry is spot on for my riding. The suspension works fine, compared to dw-Link you get more movement under pedaling but nothing that really bothers me. Superlight frame.

On the negative side, I can make the rear end squirm/feel some flex if I really push it. And bearings seem to last a season or two. Oh, rear clearance is limited. You won't fit anything wider than an honest 2.2" tire.

I agree, the frame is a little flexy, but I think that was designed in and once I got used to it I sorta like it.

Are the bearings easily & user replaceable? I know the Ibis bearings are user replaceable, with a special $60 tool. I got too many tools in my garage now.

You may have to borrow a press for one end of your shock. Mine has been ridden all over the country and carried me and my son through several race seasons and I've never had to replace anything on it.

When you said Yeti, I thought coolers. I was going to tell you to buy a Kong cooler.
https://www.kongcoolers.com/