Here are some comparative measurements with books that cover the same area or parts thereof:
Howell & Webb Mexico:1562 g, 23.5x15.6x4.5 cm, total pages 873
Vallely & Dyer CA (the new book): 1396 g, 23.5x16.0x3.7 cm, 584 pp
van Perlo/Collins Mexico & CA: 625 g, 20.0x14.0x2.3 cm
Fagan & Komar/"Peterson" NCA: 562 g, 18.3x11.4x2.6 cm
Birds of NICARAGUA: 792 g, 21.5x14.0x2.4 cm
Angehr & Dean PANAMA:834 g, 21.6x14.0x2.7 cm
Garrigues & Dean COSTA RICA (2nd ed.): 597 g,19.7x12.8x2.3 cm
(and the old Stiles & Skutch FG for Costa Rica: 910 g)
Thus, with the exception of Howell & Webb, this new book is by far the most bulky one. It seems that quality really has its price, in bulk as well. Though I think it would be possible to reduce the size somewhat. Most illustrations are rather large, and they could serve their purpose with some reduction as well. Likewise, reducing the size of the fine range maps ( they are color coded) would be possible without loss of major info. Thus, it would be mostly the text that might need some compacting without going to a much smaller font. There are 16 pages of references (677). I always wonder how useful these are in the field, or even on the average field-trip. (But where to put them to have them available at home? A link to a pertinent web-site ought to take care of this issue, actually.)
Together with the van Perlo book, this book's cover protrudes on three sides which would be another thing that could be changed to make it more compact.
The book comes with a "Fast index" distributed on the inside flap of the front and rear cover. This cover is both flexible and sturdy on first impression.
I always wonder why such books do not "automatically" come with local (Spanish) names as well. Usually, the illustrations of a particular plate are all to the same scale, and the scale is indicated in the upper right-hand corner. Quite convenient!
Aside of the often "misty" appearance of the illustrations mentioned in my previous post, the browns tend to be a bit too reddish, and some white birds, particularly the cotingas, came out too greyish. At times, I can't help myself but thinking that there is some double-printing, particularly on the bottom half of a plate.
It's clear, all my critical remarks here are complaints on a very high level. But why not strive for the best in those respects as well.