How to choose between AM230x and DHT22 temperature and humidity sensors?
The AM2301 and the DHT22(AM2303) are similar in a number of ways, both in price, specs, ranges and power consumption. They are usually cased a bit of a differently, with the DHT22/AM2303 being packaged with four pins (only three are in use), and the AM2301 (formerly called DHT21) is packaged with three cables and a small plug inside of the case.

I would choose based on the usage, if I'm going to use the sensor on a breadboard or a socket (going for the DHT22 pinned version), or if I'm going to have it standalone (the cabled one).

Here are links to the datasheets:

https://kropochev.com/downloads/humidity/AM2301.pdf

https://www.adafruit.com/datasheets/DHT22.pdf