I feel like this book has had some bad luck by becoming increasingly true and relevant. Since conspiracy theories have proliferated this decade, we're all thoroughly familiar. Although this book was there first, if you've already had a read through everything on wikipedia and countless thinkpieces on the issue, this feels like more of the basics. What might have been obscure and exciting conspiracy theories, a mindblowing social milieu, and novel analysis when presented for the first time is just not so exciting anymore.
This is solidly a good book - its just that the other Eco novels are better. The ones set in the middle ages are more immersive, more imaginative, more vibrant. It also seems like Eco is taking this seriously instead of "just" having fun. There's an analytical and didactic feel at the heart of this novel, which I didn't like.