Appreciating Michael McKean in Better Call Saul: a career best?

I have always enjoyed Michael McKean. I enjoyed his songs and his performance as David St. Hubbins in Spinal Tap, and - having grown up on Laverne and Shirley, as a child - was always positively predisposed towards him, whenever he'd turn up in something else - not that I've seen that many of his performances. I think you'd have to go back to the 2001 film My First Mister, an awkward teen-adult romance film starring Albert Brooks and Leelee Sobieski, for the last non-Spinal Tap-related feature I'd seen him in, prior to settling into my current Better Call Saul binge; before that, there was 1999's Teaching Mrs. Tingle. (I actually have not seen Best in Show or A Mighty Wind, though I am told I should). 

Michael McKean is still around, of course - this isn't an obit or anything. But I just wanted to say - if McKean has ever been better in ANYTHING than he is as Chuck McGill in Better Call Saul, I sure haven't seen it. Coming late to that show, I'm stunned by the richness of his performance, by the sympathy he evokes for a difficult character and the vividness with which he realizes that character's psychology. It's like John Heard and Cutter's Way, or Treat Williams and Prince of the City: they're also actors I'm positively predisposed to, but did either of them ever play a role remotely as meaty and rich as in those films? Are there better performances to be seen by them, in anything? I haven't seen them, if so. 

Like I say, it's entirely possible that there are other gems in McKean's filmography that I've missed, since there are big holes in my viewing, but damn does he do fine work as an actor in Better Call Saul. He plays a controlling, successful lawyer - brother to Bob Odenkirk's character Jimmy, who has not yet adopted, when we meet him, the moniker "Saul Goodman." Chuck is either afflicted with a poorly understood medical condition, or else a serious mental illness, that has him totally intolerant of - allergic to - electricity. It's kind of akin to the Julianne Moore character in Todd Haynes' masterpiece, Safe; he is adamant that the problem is a real one (and indeed, it is drawn from reports of a very real, but controversial and poorly-understood condition, which you can read more on here) - though other characters in the series prove to their own satisfaction that he's "just" mentally ill (as if that is ever the only explanation for anything; even the mentally ill are human beings, with feelings and intentions and personalities which inform and are informed by their illnesses). 

I'm loving the whole series, of course - Odenkirk and Jonathan Banks and Mark Margolis and Michael Mando and Rhea Seehorn and Giancarlo Esposito are all a great pleasure to watch - but McKean is the discovery for me. I've always enjoyed his work, but had no idea he could be THIS good. 

Maybe I WILL watch A Mighty Wind and Best in Show, now...