[avadodin]

Defaulting to a CSPRNG pre-seeded with system randomness is not a bad choice per se(especially given many users don't know they need one) but current ones are much slower than the RNGs we are discussing.

If you're going to provide a non-CS one for general simulation purposes, you probably want the one that is the closest to indistinguishable from random data as you can without compromising performance, though.

Some people will have more than enough with a traditional LCG(MC isn't even using RNGs anymore) but others may be using more of the output in semantically relevant ways where it won't work.

If Xoshiro's state can be trivially recovered from a short span of the output, there is a local bias right there that PractRand lets through but that your application could accidentally uncover.

The choice is: Are the performance gains enough to justify that risk?

[tptacek]

Why does it matter if the state can be trivially recovered? What does that have to do with the applications in which these generators are actually used? If the word "risk" applies to your situation, you can't use either xorshiro or PCG.