I played a Swordsage at 5th level for four sessions before succumbing to a CR 10 giant. I had a special maneuver that dealt +6d6 damage to large creatures, and I really wanted to try it out. Well, I missed, and the giant thumped me.
Before then, it was fun, though a little frustrating that I would just never use some of my maneuvers because it was better to use one or two and then just attack normally. I was trying to go for a ninja-esque warrior with high Jump, Tumble, and such, and lots of mobility-based powers from Setting Sun, but I tried to play like a fighter when I was really more like a monk. I died when I got too close to a big creature.
I played an elf so I could use a bow, because for some stupid reason swordsages aren't proficient in any ranged weapons. At 28-pt. buy it was hard to make a good character because of multiple-ability dependency (strength for attacks, wisdom for AC, intelligence for skill points to use maneuvers, dex for AC). Also, the fact that some abilities keyed off of using attacks of a particular school, or only when using a particular school's weapons, was difficult to keep track of.
I think that, at low levels at least, they should have simplified the Swordsage, because as is it has too many modifiers that apply only occasionally.