I saw most airings of 'Uncle Croc's Block' in 75-76, so saw quite a few M-U-S-H episodes. My impression was that it was a very lame, off-brand cartoon. In fact, I thought the quality of the Filmation cartoons on 'Uncle Croc' was the main reason the show didn't last. They were derivative and formulaic, smudged carbon copies of assembly-line 1960s animation (think 'Tennessee Tuxedo" or "Hector Heathcote"). Right before and after the show you could see 'Schoolhouse Rock', a truly catchy and innovative series. 'Uncle Croc' itself was a hilarious, forward-thinking comedy show in the tradition of Soupy Sales and Doodles Weaver. There was great Saturday-morning stuff going on in the mid-70s, but the people who made M-U-S-H didn't get the memo.
Does M-U-S-H look good as a standalone item when viewed today? Maybe it does. I'd like to take a look and see.