I have used a P850 model briefly (for an hour). I like the image
stabilization and the larger LCD. There are more buttons and settings
than your DX6490 has. I've shot a few long-range zoom images through a
store window and get good results. The camera's focus system reminds me
of that on the Panasonic Lumix FZ1 -- good in most lighting. Haven't
tried it in low light yet. I needed to set the AF from continuous to
single AF in order to get the most out of the IS technology without
feeling seasick.

Ergonomically, the camera is taller than the FZ1 and better for larger
male hands than the DX6490. I'm able to get my fingertips in between
the grip and lens barrel on the P850. I'm not able to do the same with
Kodak's other new P camera, the P880, which isn't a 12X zoom.

I'm awaiting a review from dcresource.com; Jeff is the best at writing
original commentary instead of cut-and-pasting text from prior reviews
of models from the same manufacturer.

-Cardamon

Try here: http://www.dpreview.com/reviews/kodakp850/

Gerrit