This DVD collection has been a wonderful thing, and I have been collecting all of the volumes from the start. Unfortunately, I'm sad to say, I am disappointed in the 3D content.
There are a couple of serious technical issues that prevent the 3D effect from solidly occuring. Please allow me to qualify my opinion. I have been a motion picture projection and sound system engineer for the past 35 years. Among other things, I install the various digital 3D projection systems that are in theatres today, so my gripes are coming from someone experienced in tri-dimensional imaging (ain't that a cool word?)
For a dimensional illusion to occur, there must be a means to insure that the left eye image only goes to the left eye, and the right only to the right. That isolation between the stereo pairs is key. If part of one eye's image "leaks" to the opposite eye, the effect is destroyed -- and this is the problem with the DVD; the choice of anaglyphic colors do not adequately separate the stereo pairs. In other words, you can still see parts of both eye views in EACH eye - which is almost like not wearing the glasses at all.
This was noted AFTER adjusting my CRT's color level, phasing (tint), and contrast to maximize the filtering and minimize the bleeding effects. While the green lens does filter out the magenta image sufficiently, the magenta filter only makes the green image appear dark (instead of making it invisible to that eye)... and both colors amplify themselves in their respective eyes, resulting in double outlines around everything. IMHO, they would have made a better choice going with cyan as the left eye color instead of green. Magenta and red have trouble filtering to begin with, but they work much better with cyan than they do with green.
Secondly, there are wildly varying convergence (alignment) problems throughout the films. In "Spooks," you can even see the images separate VERTICALLY in the middle of a shot! Near the end of the film, when Shemp says, "Stannnnd back, or I'll brain ya!" watch the two images drift apart vertically. Viewers can tolerate a certain amount of horizontal misalignment in a 3D picture, but NEVER vertically, because it tries to pull one eye up and the other down.
I don't really see them going back to fix this, so here's hoping it will appear in a superior polarized form in the near future, via some other conduit. If you can catch a revival theatrical screening somewhere, go see it by all means. I understand they ran "Spooks" not long ago at a festival in Los Angeles, in its original 35mm, two-strip format!