Final-ish report from a dude who preordered 6 switches for himself and his friends:
Best Buy: One in-store, one shipping. Shipped copy got in around 11AM via UPS, very early. Pickup no problem, as well as the pickup for BotW Master Edition, Pro Controller, etc. Free shipping.
Amazon: One shipped, arrived at the same time as the BB Switch. No problem. Free prime shipping.
Target: Shipped on Thursday via UPS 3 Day Select. I don't remember if I had other shipping options (this one was free), but this one was originally slated for Tuesday arrival, now slated for today (Monday). Meh. But I did get RedCard discount.
Walmart: FedEx or Walmart really goofed this one up. I did two orders. First, the shipped one: Walmart sent me a shipped email early Friday morning. The email stated the 9th as the "get it by" date, but the actual email said overnight by end of way on the 3rd. FedEx claimed this all the way through MIDWAY THROUGH SATURDAY, finally went to 'pending' after the system was still half the country away a day late, and is now claiming delivery for today.
The in-store pickup one is maddening. So I know via BrickSeek that this WalMart got 55 gray Switches. However, apparently when you pre-order for store pickup at WalMart, you're not pre-ordering one of their local stock, but they're shipping one from their online warehouse, ON FRIDAY, and you have to wait for it to get in. As of now it's still "By Thursday" and I don't know when it will actually be available, although the site's tracker says it's a town over so hopefully today. I don't know if this was their intent, but I did get an apology email for the delays and I should be getting a $20 gift card.
Moral of the story: Amazon and Best Buy did well for me, despite others having issues. Best Buy store pickup seems like the most reliable way to go, they actually do it right. Never use Walmart for time-sensitive items. Target may have been more about the shipping type, but still, don't expect free release day shipping.