I'd take Manchin over the moderate R darlings like Olympia Snow any day.
I liked her marginally more than the other Maine Moderate Darling Susan Collins (holy alliteration), but only because she was a hair more liberal. She still voted party line more often than not.
It's my crusade to show people that moderate Republicans no longer exist, at least on the national level. They became endangered with the Republican Revolution in '94 and borderline extinct after the Tea Party in '10. These supposed moderates are not the Margaret Chase Smiths and the Nelson Rockefellers and the John Warners (the 7th Mr. Elizabeth Taylor) who supported the New Deal and civil rights (but thought they could run things more efficiently), who would occasionally oppose their president's Supreme Court nominee, and who were in some ways more liberal than conservative Democrats from the south. Back then, you might not be a Republican, as I would not have been, but you could perhaps understand why someone would be.
Calling Susan Collins and Lisa Murkowski "moderate" shifts the discourse too far right and makes extreme views look centrist and palatable. It gets scarier when these "moderates" get primaried by people even loonier than they (e.g., Flake in Arizona), eventually shifting things even further right.
In short, I agree with you but felt compelled to offer my own criticism of the moderate darlings.