Canon's A-series PowerShots have a lot of fans because, along with good photo quality, they're reasonably priced, run on AA-size batteries, and occasionally have optical viewfinders. The A3100 IS and A3000 IS won't please these fans.
The lack of optical viewfinders isn't shocking; they're all but extinct. And the price, well, I'll get to that later on. But Canon scrapped AA batteries on these two, opting for lithium-ion rechargeable batteries to keep the size down. I'm not sure why you wouldn't just go with one of its Digital Elphs.
The cameras are otherwise the basic fare I've come to expect from this line over the past couple years. Both cameras feature a 4x zoom lens in front, optical image stabilization, and a 2.7-inch LCD. A couple of scene modes were added; one for bumping up hue and saturation called Super Vivid and another that posterizes photos. Canon's also renamed its 2-megapixel ISO 3200 scene mode to Low Light, hopefully ending any confusion as to why you'd want to use it.
Differences come down to megapixels and body colors. The A3100 is 12 megapixels and comes in red, blue, and silver versions. The 10-megapixel A3000 is in black-and-silver two-tone body only.
When they ship at the end of February the A3100 will be $179.99 and the A3000, $149.99. Those aren't bad prices, but with so much competition below $200, there's nothing in the specs that make these worth a second glance.