Performance: They're about equal, with the 5830 winning in some titles and losing to the 460 in others. It's the reason Tom has them rated as equal. However, I'm not sure about overclocking potential. I believe the 5830 overclocks better, don't take my word for it.
Heat: Depends on which model you get, according the Hardware Canucks review, for instance, the 5830 they were using was cooler than the 768 mb gtx 460.http://www.hardwarecanucks.com/forum/hardware-canucks-reviews/34089-nvidia-geforce-gtx-460-1gb-gtx-460-768mb-review-17.html
Noise: Again, it varies. I'd give it to the 460 though.
Power Consumption: Goes to the 460. Not by much. Edit: Actually, I take this back. Particularly after going over some of the brand specific models.