Well, I don't have experience, but I can see 4 ways:
1. Voltage divider: simple but I don't think there's enough isolation, there's too much reliance on ground.
2. Separate the ADC's Vdd and GND from the rest of the system, follow the AC ground, and of course use a voltage divider, and use an optoisolator for serial com. This is almost certainly the best option.
3. Use transformers to get voltage & current. Non-sinusoidal waveforms will be distorted.
4. Use induction devices to detect voltage and Hall induction devices to measure current. The DC value of either waveform is virtually unreadable, though there should be none in normal operation. It might distort nonsinsoidals as well, I don't know. It's expensive too, but does have the neat ability to clamp around conductors without having to disconnect anything.