I have been using it in an Eberron game that I started recently. I have 1 Kalashtar, 1 Warforged and two Dragonmarked giving the use rate for that book as 4/4. My players have enjoyed the byte sized lore bits on each of the places, because it is easier for them to learn what they need to.
In the spirit of full disclosure, I have the 3.5 Campaign Setting, Sharn: City of Towers, the 4e campaign setting and ran a 5e Eberron game for 2.5 years when 5e first came out. I would rate myself as a huge Eberron fan. I find the Wayfinder's Guide to be helpful, both for the 5e mechanics, but also for the shortened lore it gives, and the tables and ideas presented in both the Eldritch Machine sections and the Sharn Adventure ideas section.
I think as is, the book is sufficient for running a detailed Sharn based adventure with allusions to other parts of the world. If as a DM you want to run full Eberron adventures, I would suggest both the 3.5 campaign setting and the guide. The fluff has not changed, and the detail of the old campaign setting is great.