You can see new benchmarks here: Arm vs Intel Benchmarks
Basically, performance-wise, the Bay Trail z3770 chip is on a par with Nvidia's Tegra 4 and Qualcomm's Snapdragon 800 chips.
Earlier reports of low benchmarks and TDP/part numbers for Bay Trail, appear to have been fakes.
Intel is not releasing "TDP" numbers, but that may just be because Bay Trail's power management is very unusual. I think it is likely that for brief instances a Bay Trail chip can be outside the normal tablet envelope, but quickly returns to an acceptable level, making it fully usable in a tablet. Practical TDP estimates by several benchmarkers at Intel's IDF say it's something like 3 watts, which (assuming that's true in real-life conditions) is amazing.
I do have one concern though. Intel's burst mode might possibly have adverse effects on game playing. Essentially, the chip alters its speed dynamically for both CPU and GPU... that may be upsetting when playing an action game that requires appropriately timed gestures.