That's very interesting. So, my understanding is that the SX220 and SX230 are identical except for GPS - is that correct? But I am less clear on the differences between the SX200, SX210, and SX230. In particular I notice that only a few firmware versions are listed for the chdk for the SX200, which makes me wary of getting it. But the 210 is looking nice all of a sudden - it has both the highest zoom and the highest megapixels out of these cameras. (It is also a bit more expensive, I guess because its been discontinued?). So now I am investigating more comparisons between those.
I wish there were an easy way to test these out. I know I can play with an SX230 in a place like Costco or Best Buy, and I have done, but the flourescent lighting in those places is so odd that it leaves me with very little sense of what the camera will be like in other situations.