I have played characters with power attack, and DMed for characters with power attack... and, while I found it to be pretty manageable, the fact that it required managing does say something.
If there were an alternative to Power Attack that was slightly less 'fiddly' and/or slightly less breakable, that'd be a good thing, in my book.
A lot of the possible fixes for power attack that have been mentioned I think are good ones. Making power attack deal 'extra damage dice' is a good fix for some of the things that tend to break when used in conjunction with power attack, I think. Making power attack use larger increments (-4 / +4 is my favorite increment) is another good one. I am less sure of making power attack "always on", but if it were folded into a Talent Tree where you didn't actually take any attack penalties for using it (instead you give up the opportunity to take some other talent tree, assuming that all talent trees are created equal), than that'd probably be a workable idea, as well.
Until I make the switch over to 4th Edition, though, I find power attack to still be serviceable enough, even if its not the prettiest thing out there.
Later
silver