Indeed, I consider Zorro to be Toth's "Magnum Opus". I have long felt that Toth's most enervating period was the Dell/Gold Key run at Western Printing over the course of 1957 through 1961 (just before he made a return to DC), and that Zorro was his high water mark there. I have wanted this material in a format like this for YEARS now, and now we have it. I still like the classy hard-bound volumes like these, that lay flat when you read them. If you're a fanatic about reproduction (which I am very close to) you may want to try the B&W collections out there.
Let's face it you wouldn't get an exact copy of the original drawings even if they reprinted them full size.
You have to give Hermes credit for having the guts to print some of the B&W originals in the same volume as the finished product, as they did in the Phantom books. Although I don't have access to the original comics, I'm betting these are much better. This is still a great-looking collection of Toth's work, and you can see and appreciate the big bold strokes he uses, and there is still plenty of line detail.
But I think the negative reviews are a bit over the top.
Somehow coloring, at least the process Hermes and some other companies use, makes the fine-line stuff suffer a little. I read all the reviews here before buying this, and I was a bit leery because of some of the negative reviews I have other Hermes Phantom books, and I know what the naysayers are talking about.