We went in November 2019 and found it to be worth the investment. I think a lot depends on what you hope to accomplish during that time.
We (party of 3 adults) entered at 4:00 and managed to accomplish all of the following rides & character meets before we left at closing : BTMRR (FP+), Peter Pan (FP+), Haunted Mansion, Dumbo, Small World, Mad Tea Party, Winnie the Pooh, Space Mountain, Monsters Inc Laugh Floor, 7 Dwarfs (meet & greet) , Bert & Mary Poppins, Tweedle Dee & Tweedle Dum, and Pooh & Friends. We also watched the Frozen Wish show, the fireworks and the 2nd parade. We could've booked a 3rd FP+ attraction for the 4-6 window but it would've been tight and we opted for the freedom of not being rushed.
In comparison, we (party of 4 adults) went to
MNSSHP in October 2018 and managed to do the following between when we arrived (shortly after 4) and party closing: Buzz Lightyear (FP+), BTMRR (FP+), Splash Mountain, dinner at Pecos Bill, POTC, Magic Carpets of Aladdin, HM, Peter Pan, 7DMT, & Space Mountain. We stopped at a few photopass spots, watched Hallowishes, the Sanderson Sisters show and the 2nd parade. The FP+ reservations were our 4th and 5th fast passes of the day because we had been at AK earlier in the day. We did not do any character meet & greets.
One of the big differences between our 2018 & 2019 trips is that we had park hopper tickets in 2019 and so went back to MK the next day to hit up a few things we hadn't done the night before. In 2018 that was our only time for MK.
Generally speaking I get more into the spirit of Christmas than I do at Halloween so that somewhat clouds my view of why I liked
MVMCP better than MNSSHP.