The biggest gripe I found with the D3100 was the Guide Mode. What, your camera teaching you how to shoot? No way! I almost told that to my coworker, but kept it to myself since she just purchased it. We went out for a walk one afternoon two days after she had her D3100, and I taught her some things about aperture, speed, ISO and depth of field.
...and then all of a sudden the Nikon went "Error: Press shutter button again" or something. It was madness. I found out it was a common problem with the D3100, something to do with the aperture lever. I wanted, wanted to suggest going Pentax, but then again there's something about Nikon that pulls some people over, I don't know what.
The K-r successor better have something the D3200 doesn't (though I'm sure that's a lot of things, but I'm talking "marketing" for it lol). For sure the D3200 will be
yet another I AM NIKON and crap like that hah!