I've just switched from Cablevision/Optimum Online to verizon FIOS. Unless I'm mistaken, it appears that my FIOS MultiRoom DVR lacks ability to play back a recording or portion thereof in slow motion.
This is a capability that I often used on my Cablevision DVR to watch slow-mo replays of portions of a show, especially sporting events (e.g. to see if the ball really crossed the goal line or touched the out-of-bounds line, to analyze the player movement that led to a really good play, to see better a really good dive or gymnastics performance, ... ). With the Cablevision support, slow motion is activated on the remote by simply pressing the Play button when the DVR is already in Play mode.
I'd like to suggest that this capability be added to FIOS DVRs, hopefully via a firmware update to current boxes. Frankly I quite surprised it seemingly isn't already available. It's something that was available on at least some VCRs 30 years ago.