I'm guessing the player is connected with WiFi and not Ethernet? If so the speed will generally increase the closer you move the unit to your router, so that could be a contributing factor to the rip speed being so slow.
As others have mentioned above, rip speeds will vary depending on the disc involved, but MCH is always slower to extract to DSF because there is additional processing in unfolding the lossless compression called DST. The stereo tracks (usually) don't have any DST, and thus will extract to DSF faster than the MCH tracks will. Also, there's simply more channels to process, so that takes longer.
You can't elect to leave the DST intact when extracting to DSF, which is why that setting is greyed out in the GUI, you don't have any choice.