First off, the good; Great writing, acting, sets... extremely entertaining. Fun even. Well above average.
The bad; Was there anything here historically accurate beyond a Russian emperor named Catherine that took over and ruled Russia? I didn't see much. And so much of the inaccuracy was pointless and unnecessary... like Peter's father died when he was quite young, and he wasn't Peter the Great. It was his grandfather. And it doesn't stop there... For those of us who enjoy History and historical fiction, it was a bit odd and detracted from the immersion.
The profanity; I'm no prude and have no issues with the F bomb, but some of the later episodes had dialogue where it was nearly every other word. Again, this detracts from the immersion. It's jarring.
Political correctness; I have no issues with multi cultural actors. It is called acting for a reason. But painting an empire that had already had female leaders as some sort of boy's club that needed saving by idealistic young Catherine? Not even close to real, and again, slightly annoying. Catherine was a tomboy, loved horses, shooting, hunting, etc. She was not a dainty little thing dreaming about art and education. That movement had already been started in Russia years earlier, some of which was expanded by Peter, and some subsequently rescinded by Catherine.
I did like the way they explained the old gossip about her sleeping with her horse. Clever, and could very likely be what happened in reality.
With just a bit more effort in the writing to be true to History and the actual characters, this could've easily been a 9 or 10. I'm not expecting 100% accuracy, but something higher than 5% would've been nice.