Just finished the two part finale. As a kid, I watched the series in real time. I still watch TOS on DVD. I have to say this was an excellent bookend to it. As everyone else has noted, it was strange seeing new actors portraying the characters. I got over it pretty quickly. It truly looked and felt like these were the "lost episodes" of TOS.
Congrats to the cast and crew for pulling it off. I hope the brain trust is pulled in by Paramount to officially do some Star Trek work.