AC current measure using CT, 10-bit 200 ksps (mcp3008) or 12-bit 100 ksps (mcp3208), which is better?
Having read a development specification for power-meter IC,I recall the sampling rate for both I and V was 14,000 samples per second.

I suggest the higher resolution ADC that only samples at 100,000 samples per second.

The house wiring provides inductance, to assist in filtering the SwitchReg surges.

Power Meters, to be certified, have dynamic range and accuracy and deadzone requirements. 

....If I recall correctly, these meters must NOT have extra counts with ZERO load power.

....Under a mere 10 watt load, the meter must begin incrementing the total-power accumulator. [and probably with some % error, but I don't recall that tolerance; Analog Devices Inc has such ICs; read their datasheets or AppNotes]

....under a 10,000 watt load, the meter must accumulate the total power with less than 1% error. [ or perhaps even more accuracy; but you want to learn, not develop a product to sell.]

Notice the requirement to recognize a 10 watt load, but accurately digitize a 10,000 watt load, requires 10,000 / 10 = 1,000:1 dynamic range or nearly 10 bits.

Thus I suggest you go with the higher resolution ADC.