They're all the rage, and rightly so. Soft and squishy and ruffled, you can have one to match every outfit if you like.
The only problem with them is that they're a pain in the backside to knit. You're using a net-like yarn that's about 2-3 inches wide and knitting through the edge of it. You have to stretch it out as you go (or unroll it, stretch it out and re-roll it onto a piece of cardboard). Either way, it's a pain to do that.
The upside is, once you adapt to the netting, things go a bit more smoothly and faster. There are any number of youtube vids about how to do this, along with any number of brands of the netting yarn.
I'm making my first one with Red Heart Boutique Sashay in the Waltz colorway. Take my word for it, it'll look crappy when you first start, but give it a foot or so and it'll start looking really nice. I'm going to give this one to a friend for Christmas, she likes the browns and blues in this particular colorway, so it goes to her.