Right off the bat: brilliant.
So the plot is that in the future, we can send historians back in time (if the conditions are right). The protagonist, Kivrin was supposed to be sent back to 1320 but instead ends up at the height of the plague in 1348. At the same time, chaos breaks out in Oxford with an unknown virus taking out the tech operating the 'drop' into the past as well as many other people in Oxford.
So there's parallel tension ratcheted up throughout the book of the events in 1348 and in the modern day. The modern day had recently experienced a global pandemic so Oxford gets locked down in quarantine.
I originally thought (about 200 pages in) that it could have used a judicious edit but by reaching the end, I don't think you would have ended with the ridiculous amount of tension, so it wouldn't have been so satisfying.
I think what was utterly brilliant was that it totally passes the test with flying colours.
I would say that there are more female characters that are main characters than male characters. Kivrin is amazing and resourceful, determined and focussed all the way through. All the words describing her are positive. The othe female characters are equally professors or doctors.
There are both annoying male characters and female characters. Basically, gender balance is fucking brilliant.
What was even better was that while one of the main male characters, Mr Dunworthy warns that there are cut-throats and rapists in the medieval period (which doesn't dissuade Kivrin from going) this doesn't actually happen when she goes back. All the threats are things like disease, the mother-in-law of the woman who takes her in, or unknowing where to go to get back home. They are all things that she uses her resourcefulness to overcome. She is utterly strong and amazing as a character. I wished I had read this book as a teenager.
When there is some less salubrious relationships (basically a 12 year old is betrothed to a 50 year old in 1348) it's clearly viewed critically and disapprovingly by Kivrin. Which is so much better than how it's usually portrayed (as just the way they put women in danger).
I think from a historical standpoint, we've moved on a little bit from the image of the medieval period portrayed in the book (but not a whole lot). As well, the slight anachronism of not having mobile phones took me slightly out of the story. One of the key plot points was not being able to get through on the phone lines and not being able to find the head of the department (which wouldn't have happened now).