My grandparents went both ways. My grandma was healthy and active until the morning she didn't wake up. My grandpa on the other hand. had a few strokes and lingered in an adult foster home not knowing who anyone was for 5 years.
Grandma was a giant shock. Like boom. Gone. But we all pretty much figured out that hey. I wanna go like that. It still sucked but hey. My grandpa on the other hand, when he finally did, it was a relief. Like thank god he finally physically died. he had been mentally gone for years.
On the other side of the family, my great grandma had alzheimer's the entire time I knew her. From earliest memories when I was 3-4 till she passed when I was 9. Not a way I would want to go. No one was overly sad at the funeral since her mind had been gone.
For me, 100% rather have the drop dead. It sucks, but you knew they didn't suffer.