I used 748 & Varget for years.
748 is dirty, but it shoots good,
Varget got hard to find when everyone lost their minds.
I haven't tried hot days yet with Benchmark,
But with 55-60 grain V-max bullets, about 26.5 grains is about as accurate as anything I've shot so far in 40+ years of reloading for .223 rem.
When we get some warm/hot days I'll see if it has the same issues with temperature that 748 has or not.
Most people say it doesn't, which is why I picked it to try.
The issue I had with Varget was when I loaded light weight bullets.
Varget starts to really shine around 65 grain bullets and up,
Although I had a Ruger M77 mkII that shot Varget and 55 grain bullets really good...
Varget can be a little heat sensitive when it gets real hot...
Benchmark is EXPENSIVE around here, but its working really good for me so far.
'Felt Recoil' is a function of gas VOLUME hitting the bolt/carrier.
Even 'non-adjustable' AR style rifles can be tuned for a specific load pretty easily and cheaply.
Since this isn't a 'Smith' forum, and I've been 'Warned' about giving 'Smith' information in the open forums,
Send me a PM and I'll explain how to tune your gas block port for about any load you choose.