Counter based pseudo-random generators like Random123 use cryptographic transformations upon counter variables, and were rigorously shown to pass all standard tests of randomness of distribution. However, these tests were done using AES, Threefish, and Philox, and do not automatically apply to SHA256 that James uses. The advantage of these is that they allow direct construction of the Nth element in a pseudo-random sequence without large memory or CPU usage needed to construct the N-1 prior elements.
That said, Random123 is *done right* by a number of very brilliant people who performed rigorous testing. Something that "seems kinda similar" may or may not be of similar quality (more likely not). FWIW, AES is built-in as a primitive instructruction on most modern general-purpose CPUs, so can be very fast to perform.
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Keeping medicines from the bloodstreams of the sick; food
from the bellies of the hungry; books from the hands of the
uneducated; technology from the underdeveloped; and putting
advocates of freedom in prisons. Intellectual property is
to the 21st century what the slave trade was to the 16th.