The whole "recruiter's view of 135 PIC time equal to 121 FO time". Come on man.
There's all kinds of 135 operators. Now, if you're flying 135 in a caravan or a twin piston then yes, I can see that time being viewed as 121 FO time but... 121 FO's are being hired with the majors and many have 0 PIC.

FWIW,

I've got 5500tt, 2500 TPIC, all in a King Air 200, all part 135, and the majors are not calling me.

Maybe it's lack of jet time? Or maybe it's because I have about 6yrs 121 experience before leaving for 135?

A friend of mine flew 1900s at Gulfstream for a couple of years, he left to fly bizjets for a bunch more years, all short or medium range. Tons of PIC time he got. He got on with United last year. Moral of the story is I don't know what this proves other than he did it with some 121 PIC time on his resume.

I think we're both making the same argument. The recruiter didn't care (and came from a part 135 background themselves) about part 135 vs part 121. I specifically asked that because I have the opportunity to go part 135 or to a regional, and I wanted to make sure I wasn't going to shoot myself in the foot if I took the Job that would give me a better quality of life.

The point I made was both are viable paths to the Majors to counter the argument being made that the 135 PIC time would be worthless and the guy would be better off skipping upgrade to be a FO at a 121 regional and never having any PIC time.

Take the upgrade. Can't beat having experience as a captain on your resume. Get some PIC time then go apply at a LCC, then check the 121 box.