Tome of Battle classes are about as powerful as Tome of Magic classes. They're better than core Fighters, Paladins and Rangers, but less powerful than Wizards, Clerics and Psions.
Compared to a Barbarian, the Warblade is about even--a well-built Barbarian will outclass a Warblade in terms of pure damage output, but the Warblade will be capable of other, more interesting things, like altering the initiative order or shaking off an ongoing magical effect. I'd put the Crusader just a hair above them both, but still far less powerful than a decently built Cleric. The Swordsage is really more fun than good. He doesn't have a role in the party that we think of as canon to the D&D experiece, but he's very good at dealing nice damage, bouncing around the battlefield, and looking stylish while he does so. He's like the monk class you've always wanted, and I'd measure him to be a bit more combat effective than a rogue, but beyond acrobatics he's not much of a "skill-monkey."
I wouldn't be all that concerned, frankly, with the Tome of Battle classes outshining other classes in terms of pure effectiveness, although they're all a sight more powerful than Monks and Samurai.
But if you've got a party with a Fighter, a Rogue, a Barbarian, and a Swordsage, the Swordsage player is just going to have a lot more fun in battles, with a lot more options to play with. Your other players will probably get jealous, but not because the Swordsage is strictly better, numerically.