Got mine on Thursday and spent my whole Saturday with it.
Easily my favourite piece of Nintendo hardware since the GBA SP. It looks and feels like a premium device, but it still has a really fun, inviting and Nintendo-y look about it - at least in the Neon SKU.
The actual switch gimmick is pretty magical, and the convenience is revelatory. I've played all over the house, and I'm definitely considering getting a second dock once they're available or if a third party comes up with a solution.
It is odd going from a state of the art handheld experience to a roughly-last-gen console experience, but the adaptability of the Switch more than makes up for it.
I was worried for the Switch after its terrible reveal, but I think it's gonna do well. It's been a long time since Nintendo's had hardware that is as exciting as the software, and now that the latter doesn't have to do all the heavy lifting in the marketing, it's easy to imagine the Switch proliferating once people start encountering it via friends/family/colleagues. It's just a very want-able device.