That sounds more like user-error, or you've corrupted the hard drive somehow.
That said, I've had some problems with TrueCrypt:
- It falls over with big files. I found the throughput to a TC volume dropped to a few KB/s copying a 90GB file to it. I work on professional video compression tools, so I have a few files this size and larger. Google revealed a few other people have encountered the same issue
- There's a bug somewhere in the Windows version of TC that prevents it releasing drive properly. I'm not sure how people use this with USB flash drives, but when I tried it with an external 4TB USB drive, I was unable to safely eject the drive after unmounting my TrueCrypt volume