We've gone back and forth for a while about upgrading, especially after having to have my trusty 30D repaired twice in the past year and a half. Then we decided to be extravagant and wreckless and just go for it, counting this as my birthday/christmas/Marcy-survived-the-summer/Zachs-got-a-job/etc gift (though some would argue this is a gift that benefits the whole family, ahem).
Below is a bunch of Random Shit I Took Pictures Of while first testing the camera out friday night. They're really, really crappy pictures, except they're also INCREDIBLY AWESOME in that they were taken at night in my dark house and are remarkably un-grainy considering they were taken at ISOs of 5,000-12,800. So, yeah. (all of these are straight-out-of-the-camera jpegs, using my sigma 50mm lens)
f/2.8, 1/800, ISO 10,000
f/4, 1/125, ISO 12,800
f/3.2, 1/160, ISO 12,800
f/3.2, 1/160, ISO 6,400
This one's from this morning. And sure when looked at blown up it's noisy and not that sharp, etc etc... BUT it was taken in a very dark room at ISO 25,600 and is actually usable. That just blows my mind.
I'm also really loving the wider perspective of the full-frame sensor. It's made my 50mm lens more usable again and I'm looking forward to trying out my 35mm on it and seeing what that's like. For one thing, it helps make for easier handheld mama-and-me selfies (you can see how thrilled D is about this).