RandomNumberGenerator vs Aes generate key. Which should I use to get myself a key when using AES encryption (C#)

So I was checking some implementations online and I noticed that some people use the following way to generate a key:

        using (var random = RandomNumberGenerator.Create())
        {
            var key = new byte[32];
            random.GetBytes(key);
        }

While others use the generateKey method which is built in the AES class:

        using (Aes myAes = Aes.Create())
        {
            myAes.GenerateKey();
            var key = myAes.Key;
        }

Both of them are in the System.Security.Cryptography library, just wondering if there is an actual difference between them and if yes which one should I go with?