I have built several of these using ADI ADUM3166's and ADUM4166's. I've had zero problem with noise. But, you have to use good engineering practice in their design and execution.

The effective primary to secondary capacitance in an actual circuit is something less than 10 pF. Is that low enough? Depends, I guess, on what you're trying to do and what the circumstances are. 10 pF is around 500 Ohms at 30 MHz. I've built and measured some common mode chokes that had 20x that amount at 30 MHz.

Clarke