I have a Canon Powershot with the 580EX at my office for digital capture of my surgery images - not only have I found the eTTL to be very unpredictable so that I just use manual now, I have also had numerous failures of the strobes requiring repairs.
Interesting ... I have found that the 430EXII and my Powershot G9 produce amazing good results in TTL mode - particularly with a bounce. This was my first TTL flash setup ever, and I was really skeptical, but when I bounce the 430EXII inside I get really good results. One thing I find annoying is the auto-WB never gets it right with the bounce flash, but the exposure always spot on. I especially like shooting with the .56x W/A converter and the 430EXII inside.
Biggest annoyance is that it won't do TTL flash in Manual Exposure mode ... silly move by Canon.