Ranked in these QuestionsQuestion Ranking
Pros
Pro The Netflix series is motivating for some people & keeps thrift stores well-stocked
Too cheesy & fake (reality) TV for me but I've seen entire families get taken over by the kon mari craze. The thrift stores are overflowing with good stuff right now thanks to her popularity.
Pro Helps you prepare for the worst: decluttering after someone has died.
Decluttering is hard enough when you're alive & healthy & dealing with your own cr4p. It's a million times harder when you are stricken with grief after losing someone you love, and are forced to go through EVERYTHING that they left behind. If you've ever had to experience this first hand, you know exactly how devastating it is, and why you must declutter your home now, in order to spare your children. (See also Swedish Death Cleaning).)
Pro Revolutionized the way you fold things
Instead of folding shirts and stacking them one on top of each other, and then putting that stack in a dresser drawer, Kondo encourages you to "file" your clothes as if they were folders in a filing cabinet. (You either hate it or love it.)
Cons
Con "Does it spark joy?" can be a bit cheesy
Kondo encourages you to hold each possession in your hands and ask if it sparks joy, as in, does this inanimate object spark any excitement/nostalgia/appreciation/pride in your soul? If so, perhaps you should keep it. If not: thank it for it's service to you, and then remove it from your home (donate/upcycle/re-home/sell/trash).
Con Some people don't like her folding technique so they dismiss the whole book
It's OK not to follow her folding technique precisely. Most people just adopt what they like and improvise the rest. Just use whatever works for you & your family. No need to toss the baby out with the bathwater; the book still has some important insights on minimalism, smarter-consumerism, and chores/laundry/home organization.
Con Not sure "Marie Kondo" actually wrote this book
I was skeptical about the author's background when I read the first book. But now after seeing the Netflix show, I'm pretty convinced that young lady is just an actress pretending to be a quirky best selling author with . She might even be a decent organizer herself, especially after all the media tours she's done. But the Marie Kondo shown on the Netflix series comes across as a caricature of a stereotypical Asian woman, as imagined by a stereotypical dumb american who never folds & puts away their clean laundry & has accidentally allowed way too much sh17 to collect in their house.