I don't read the comic book Promethea. By this I mean, that I don't read the periodical Promethea, but I do buy the paperback collections when they come out. I do it that way with most comics I read, since the paperbacks look nicer on the bookshelf, are often easier to handle and to hand out to friends, and with a collected edition I don't run the danger of my comicshop forgetting to order an issue and leaving gappy holes in a storyline again. I generally prefer the paperback format and will keep on buying papaerbacks of series I enjoy in favour of the single issues. Still, I frequently get the impression that I am missing out on something, that maybe those flimsy single issues, whose death has been proclaimed several times in the past, are the way that Promethea is intended to be read.
Firstly, there are the outside factors. As is the case with many comics, there are many fans of Promethea who exchange ideas when new issues come out. There are online-discussions about what they like or dislike about the latest issue. With Promethea these discussions seem to be quite fruitful. Sometimes the readers incite each others' creativity with predictions and speculations and simple anticipations as to what might happen in the next issue.
Then there are the annotations to the series, which actually help adding another layer to the enjoyment of it, an enjoyment, that is still increased more, I imagine, by contributing to the annotations. In the current situation, though I steer clearly away from online-fora that discuss the series, because the paperbacks haven't covered those issues, yet. Sometimes I dig out the threads after I got the latest paperback, but reading year-old messages passively is just that: passive and devoid of activity. Same goes for the annotations; by the time the paperback comes out, the issues in case have been examined and dissected very thoroughly (but I do have to bow to all the people involved who discovered elements that completely passed me by).
These elements are valid for any comic that gets discussed on the internet to some degree, though, and I don't think they pose a major problem. What makes me occasionally flirt with the idea of switching from collected editions to single issues are features of the comic itself.
Alan Moore, as most people who are likely to read this are apt to know, is a master of the comics form. Promethea is an example for his skill of handling the comics format as well. Firstly, there is the emphasis on writing a self-contained story for each issue. While many comics nowadays seem to be geared towards eventual publication in paperbacks, Promethea delivers a satisfying story in each issue while still weaving a larger plot, and this is a good thing. Unlike other paperbacks I don't read Promethea in one sitting. Some issues are packed so densely with ideas and information, that I need a breather after finishing it. The most extreme case that comes to mind is Metaphore. With its several layers and ways of following the images, this issue just screams to be read and reread, which seems to be intended, as is indicated by the way that the last page of the story seems to be flowing into the first page again.
Self-contained issues can contain elements that are jarring in the collections. Pseunami is a sideways story, where you have to turn the book by ninety degrees to read it. While the reader of the single issue reads that whole comic that way, the paperback owner has to do so suddenly and abruptly for one chapter only. Ironically, Alan Moore himself has used the sideways device more elegantly before in Saga of the Swamp Thing. Here, the turning of the book is introduced slowly through the panel and page layout, starting from an "upright" position and leading back to it, so that this story is more easily integrated into a collection. On the other hand, elegance and collecting probably wasn't the point of Pseunami. The sideways format of this issue is mostly a representation of the "Widescreen Summer Blockbuster" feeling of the story.
Actual problems for the reader arise with the production of the paperbacks. The quality of the books' stitched binding is better than that of many other others available, which is something I applaud. Like any other perfect bound book, as opposed to stapled comics, some milimeters of paper are swallowed in the binding, though. With most comics this is no problem, as there are margins around the images. In Promethea many panel borders by artists J.H. Williams III, Mick Gray and some guest artists serve more than just containing the image. They contain symbols and representations of story elements which enhance the atmosphere, but unfortunately not all of them can be seen, due to the binding.
Worse yet, the creators frequently use double page layouts with images stretching across two pages. While this kind of layout is easily evident to a reader of a stapled comic that can lie flat, paperback readers who expect a traditional top to bottom layout can easily miss the fact that there is no panel border between the two pages. Problems in following the images can even arise when the reader is aware of the nature of the layout. The issue Mercury Rising contains a double page spread of a Moebius strip that is meant to be read by following the flat surface of the strip. Unfortunately a twist in the strip is lost in the binding of the paperback, so that the reader is likely to follow the wrong path, which leads to a frustrating moment when one realizes that the page was read incorrectly and has to be read carefully again.
Sure, Promethea is not the first time that Moore uses the comics format in innovative ways, and one person's innovation could be interpreted as needless gimmicks by someone else. Some elements are even retreading grounds he has been to before, like the aforementioned sideways issue. On the whole, though, each single issue of Promethea presents enough content storywise and formal ideas to make the series one of the few publications in today's market that gives the reader enough good reasons to read the single issues, even when there is reason to expect a collected edition.