Your DSO is probably trying to look for a sine wave so perhaps that's where the 60/120Hz is coming from (rectified 60Hz really becomes a 120Hz repeating signal).

You can just view it yourself and measure the high low points. AC couple the input (which removes the DC) and zoom in the vertical axis to see the ripple. Do this on the 5V and 3.3V lines likewise if you want to check. At the end of the day they are the most important. I would expect to see something of the order of tens of mV on the 5V line but the 3V should be fairly smooth.

A couple of percent ripple should be OK. Main thing it will affect is the lifetime of that frontend filter cap.