Markomuel: I too have the ZS3 and from pictures I've seen this 20x zoom baby may just have the same or even better IQ. If so than I can’t wait to update for all the new features including the impressive zoom, great burst speed, ultra-fast focusing, great low light capability, AVCHD format, 1080p 30 in MP4 format, GPS, and the list goes on. No, the shutter doesn’t stay open for 60 seconds, it’s a travel zoom. I don’t want to carry a tripod when I don’t take my Rebel. If 20x zoom is not important than definitely get the Canon S100 for the F2.0 and larger sensor. You can't compare this thing with bigger cameras!
The ZS20 is obviously designed to be the smallest with the most.
The ZS3 is about as big as I want to carry on my belt. The ZS-20 is substantially thinner by 5mm!! (Same as the S-100). That, and hopefully a decent IQ, is what will sell it. Images I've seen are good but I’ll need to take my own before I can judge if this is the one that will replace my ZS3.
Although they look the same size on paper, the S100 is significantly smaller than the zs20 when you see them side by side.