Overall, I've found epicwords to be slightly more feature-packed than obsidian portal, but it's a consideration that, for me, would be secondary to keeping things on sites I'm already visiting. Assuming this isn't a factor for others, I'm trying to think of EVERYTHING I would want an electronic campaign manager to do, and list it here, so that those who are more experienced with the various assistants can comment on how well or how poorly each feature is implemented. I've used Obsidian Portal a little bit, but am much more experienced with Epic Words. If others post the relative implementation of other sites' features, you can determine what features are more important to you.
Session Summaries. Often this seems to be just the DM's job, but it's nice to see players at it too (I know many games that give a player some kind of reward for doing this work. Probably the most essential part of a campaign manager for many, with the probable exception of play-by-post games.
Epic Words has a pretty thoroughly implemented
Journal system. The entries can be commented on, connected to a particular session (and thereby to loot), annotated with keywords, and made private for only specific viewers. Actually, aside from PMs, this is the only way to post stuff restricted to specific viewers, something I wish Epic Words implemented in various other parts of the manager. Bb code is supported, and a useful preview panel appears during composition, helping avoiding screwups with the tags. This last feature is available throughout epicwords.
Wiki are fundemental for those who wish to track an array of information online. The ability to link related entries among each other (hopefully automatically, whenever they are mentioned) is one of the great assets of computer-assisted managers. However, this does take some amount of data entry, and, as is the case with anything requiring work, is often a neglected portion of managers after an initial spurt of goodwill.
Epic Words has three different types of wikis, all of which permit alternative names for any entry (I usually use first and last names separately for NPCs, and both the noun and the adjective for locations) and bb code. The first, I was told, is for longer entries, and does not hotlink automatically - I'm not sure of the utility here. The second hotlinks automatically and has a couple of attractive features:
- the entries can be grouped into categories (I've found it useful to group information by the region in the campaign, but you can add as many category names as you want),
- each entry has a short description (which appears as a mouseover text box so you don't have to click through to just remember the jist of an entry), and
- each entry has an optional section of GM notes that are only visible by the GM. I wish there were a more granular implementation of this, so that some parts could be revealed to this or that player (or character). But it's better than nothing.
NPCs are most useful in play-by-posts, but tracking and describing them is otherwise useful, even if only to flesh out the setting a bit.
EpicWords has a duplicate of the second type of wiki (see above) that is used for NPCs. NPCs are also "merchants" which allows them to own items visible to the players on the item tab. All NPCs can have an avatar and GMs can post as NPCs. Personally, I find connecting an image to a character immensely useful to quickly identify them.
Item Tracking is a section that requires, again, some labor, but I find useful to avoid duplication of common items, tracking resources in "gritty" campaigns or when, for example, crossing a desert. It also has some utility for players in campaigns with lots of items: since all the items of all characters might be visible, an item forgotten by one player might be remembered by another.
Epic Words has a very detailed "Loot" tab that has both a detailed and a quick entry method. Items can be assigned to one character or another via drop-down menu. Each item has a quantity; value; checkboxes for masterwork, magical, identified, equipped and consumed; a type (offering a long list of choices via drop-down menu with descriptions such as ammunition or book or amulet); a description that supports bb tags; where acquired; when acquired; and the session on which it was acquired (which helps prevent distinguishing similar items).
Character sheets are indispensable for some campaigns, but of negligible utility to others. I've never actually tracked my character on a campaign manager during play, but I find it very useful to refer to between sessions. I imagine that most people would make a similar (albeit not identical) use, but that's a big assumption.
Epic Words allows characters to separately describe a decent variety of details short and long: gender, race, class, role, appearance, background, and so on. Also, character activity is tracked, and posting colors can be edited. An image can be associated with a character, again, a useful feature. There is iplay4e integration, if you playe 4e and use iplay4e. Characters can be retired or deleted.
Quests are an often-unused feature, since they require clarification of character roles within a situation that is usually pretty dynamic, but are useful when missions are simple, or to track several long-term goals.
Epic Words has a detailed quest section, reproducing the second type of wiki (see above), for each quest. Further, quests can be nested, and classified as minor or major, and tagged as active, pending (which keeps it hidden from players), completed, failed, or abandoned.
XP & Level tracking is, again, useful if you use it. Those who don't track their characters online, have little use for this, but it is nice for the DM to just be able to give everyone a reward or a level up without having to communicate it personally to each player.
Epic Words has customized xp tracks for different systems, and lists each PC and their history and current situation.
Forums are useful if you have players that are frequently online, and want to keep discussions in one place. Or, if you want to play-by-post.
Epic Words has a complete forum (with bb code and always-on preview) for each campaign, with threads that can be grouped together and posters can post as players or characters. There could be a more support for admin actions, such as splitting and merging threads, but I can't really say that I've found a serious problem with this fault.
Tech Support is a telling feature, in my mind. Errors happen: this is intrinsic to the human condition. The ability to fix them and the availability of those who can is telling about the care that goes into a campaign manager.
I've found that the one guy who runs EpicWords is very available. The exception to this was one period of a couple of months during which he had some personal issues, but this, as far as I know, has happened once during the past five years or so. He posts frequently on the site's discussion boards, and responses are pretty prompt.