Going quite frequently in Argentina, I found AR the best way to burn my Flying Blue rupiahs...
So I fly sometimes with AR (and sometimes with LAN).

The premium zone is going to disapear...one day but when (I red 2019)... I believe that if you may buy W tickets you don't have to worry.
You will get a seat configuration like AC E190 1+2
Don't expect a lot about drinks (poor: water, coke, coffee...) and food only some treats or if you're lucky as allready said a service station ham and cheese sandwich.

About the strikes, quite an eventuality there (as a frenchman ...) I would fear more a strike with LAN argentina (one occured few days ago and seemed very strong) as LATAM is downsizing LAN argentina...
About other delays, cross fingers it's winter time.

All my last flights with AR in 2018 and 2017 were well on time, delays for argentinian and "cabotage" flights (delayswho made the reputation of AR) are not so frequent nowadays.

This said, I would choose the AR option...but everything is possible here (even with your 10 hours before LAN flight). "Es la Argentina"