Buckle in because I had a lot of thoughts on that one!
The first of them being: Wow, what a whopper! I will admit that the only reason I got through this at all was the wonderful full-cast Podrama I listened to. I mean, which Podfic usually has dedicated chapter art and an original soundtrack? Pretty amazing. CoT had been on my list for a while for the legacy factor that it holds. Overall, it eventually grew on me to the point of being a bit sad when I finished, and I have tremendous admiration for the sheer length of the story and the way it waved throughout so many storylines by the end, but I will admit it wasn't smooth sailing all along.
For one, there are a LOT of side characters and original characters that I simply .. didn't particularly care about until maybe 2/3 into the story? Another thing that made it difficult for me to stay engaged was the non-linear timeline. It reads more like a collection of short stories, and due to that I simply didn't quite find a red thread to follow in the earlier chapters. Not necessarily a bad thing, but also not something I am usually drawn to.
That being said, what it is quite phenomenal at is a meta-study into fandom, and generally GO fanworks predating the TV series. Extra points go to the progressiveness shown throughout the entire work, the idea of the South Downs Cottage as a semi-sentient character, some minor short scenes which I ended up absolutely lovin (i.e. the POV of the St. James Park groundskeeper watching Aziraphale and Crowley for over 40 years without ever interacting) and - last but certainly not least - the DUCKS, which are now my favourite characters xD