“Teensy is a great piece of kit and full deserves the 5 stars, but..
I always buy the unsoldered (without headers). I ordered 3 of these as unsoldered were out of stock, and all headers were misaligned. Two of them have caused me a lot of trouble (disconnects and hangs as if poor power contact) and I might just return them rather than try to sort their issues. Do yourself a favour, buy the unsoldered ones and solder yourself (also, it's just the main headers that are soldered - ethernet, USB etc are unsoldered).
I've bought dozens of Teensy 4.1 unsoldered, and never had an issue with a single one until these soldered ones turned up. Disappointing to say the least.”