I've seen a couple over the years: Robin Hood, Twelve Chairs, Blazing Saddles, and most recently Spaceballs. I found them all funny, theoretically, but they rarely got an open laugh out of me. It seems like most of the time this is just because the comedic timing makes every joke or funny bit land very awkwardly, or with just a bit too much space to leave room for any subtlety or reward for the watcher.
I feel like I remember the few I saw as a kid being funnier at that time. Is it just because my brain has been attention-poisoned with the rapid fire wit of modern comedic television?
That kind of comic pacing was considered fast for the time. Brooks came into his own as postmodernism made its way to the forefront. His comic style is shaped by this. His philosophy was to throw everything at the wall and see what sticks.
That being said, Blazing Saddles is the only one that still makes me laugh. The scene where Jim makes a frowning Bart crack up gets me every time because it feels like Cleavon genuinely didn't know what was coming.
I've always heard it told that he was in fact not told the punchline before filming and was just told to try and not laugh no matter what.
Blazing Saddles is the one I found funniest and well-paced of the four I listed, for sure.