I mucked around with a few but found them quite restrictive and generally only pushed issues around as opposed to solving them. As soon as you're dealing with a nasty API you can generally find the limits of a framework and have to start writing your own work arounds to behave inside its designed parameters.
Essentially I've found jQuery the best option as a framework, and only because it reduces the verbosity of straight Javascript. Everything else, as noted above, usually ends up in the "good at first then in wish I didn't" basket.
At the end of the day, the majority of what I do is binding, validation, and event handling... and no framework really reduces what has to be done, they just stops other people from doing it differently.
Essentially I've found jQuery the best option as a framework, and only because it reduces the verbosity of straight Javascript. Everything else, as noted above, usually ends up in the "good at first then in wish I didn't" basket.
At the end of the day, the majority of what I do is binding, validation, and event handling... and no framework really reduces what has to be done, they just stops other people from doing it differently.