I don't know about manipulating equations "with flair and elegance", nor do I particularly like Sachdev's way of doing RG in bare perturbation theory (dude, using the renormalized version would have saved you several cancellations in each and every 1-loop calculation!)
But then, Sachdev gave about the clearest possible explanation to every topic he touched in the book. For instance, even though not the main focus of the book, his derivation of path integral for a spin is far superior Fradkin's version, and Fradkin himself co-invented that formulation.
If you happen to be thinking about reading Fradkin, ditch it. Get Wen and this book....Continua