I have, from just looking at the first few pages, the sense that this book might do for Eriador, what The Heart of the Wild did for Eastern Rhovanion - that is expand it into a breathing, living world that is interesting to play in, rather than just a chunk of wilderness. That sets the bar very high, so it'll be a most interesting read to say the least.
Well, wow, that was some excellent writing and very decent material right there. Who's the author? Ah, Gareth, of course, leading a great team of writers. Reading this book was a joy and it's the best book by far for the line in many years in my eyes. A feast of plenty if you will.
But, a HotW this is not. Part of it is probably due to the differences in how the books are constructed and what each book is trying to achieve. Whereas HotW was clearly meant to be the definitive region supplement for both the Vales of Anduin and Mirkwood - RotLR is a much more fragmented product, sprinkling its diverse content all over Eriador. In HotW, the focus on regional descriptions and world-building was complemented perfectly by the later release of Darkening of Mirkwood, which added the actual campaign narrative that HotW did not touch upon. RotLR instead has both location descriptions and campaign material, and as such it certainly does much to whet the appetite, but is ultimately unable to provide a full meal on either end. Most of what RotLR touches upon, it does competently, but, due to the incoherence of the material presented, reading it almost left me even more confused about how Eriador might work as a setting, than I was before. A living, breathing world Eriador is not, at least not yet.
In all fairness, I do admit that I don't believe that RotLR was ever intended as a HotW for second edition. A more apt comparison is likely to be Tales from Wilderland, an early campaign supplement to keep gaming groups occupied while the writers toil away at future works. As such, I believe that we will see volumes that do focus more on creating a coherent campaign setting by fleshing out the cultures and areas of Eriador in a more comprehensive fashion and also a more fleshed-out campaign narrative. Within such a context, I will likely look at RotLR in a new, even brighter light, as a complementary volume to these other supplements.