One of the reasons that I am impressed with the Kant-Fries School of thought is personal experience. I know that can not be used as a proof for a philosophical idea, still for me this made the idea of the Friesian School highly credible. I mean to say that Kant  tries to find a justification of the synthetic a priori by means of structures that are already placed in the mind. And thus to him, reality has to conform to the mind. If you find this doubtful, you are not alone. So the idea of non intuitive immediate knowledge made more sense. That is that there is knowledge that we know not by reason and not by the senses. And this gives the beginning axioms upon which the synthetic a priori can be built.

[I mean to say that my own belief in God is not based on reason, but can be justified by reason as we see in Kurt Godel's proof of the existence of God.  While this proof is solid, still there is always room for doubters to doubt. So for me faith comes above reason. And faith is immediate non intuitive.

[If Fries was accused of psychologism that is not really all that accurate since he was only saying we need to inspect ourselves ["know thyself"] to see the source of this faith, but not that it depends on the mind.]

And even if other things he got wrong, that is not a reason to discount what he got right. This is like what the Rambam wrote about Muslims. He wrote "If they lie about us, that does not give us a reason to lie about them."