Currently on the Equinox, we had the basic WiFi but upgraded to premium before boarding, I wouldn’t call it premium but I’ve had no issues in streaming video - YouTube, Amazon Prime etc.. with very very little buffering (we watched a 1hr video and it buffered once for about 5 seconds). I’ve not noticed any slower speeds at any time of the day or night. My biggest bugbear is swapping between devices and trying to get each device to recognise the login splash screen
I even did a video call for about 40 mins and it didn’t buffer once and it was in the middle of a sea day in the Caribbean