SocialList allows you to control more display parameters from simple pop-up menus than anything else out there. You can position the icons anywhere you want; you can exclude it from the Front Page and from static content, manage the size of the box, etc., without needing to muck with the PHP file.
The downside is that you have no control over which bookmarking services show up in your display, nor over the order in which they appear. The icons are imported from the SocialList website, and the order in which they appear is a function of the Javascript that runs on that site. For example, we want Reddit to appear among the first 9 icons displayed, but we have no control over that.

This is a prerequisite for some of the author's other plugins and modules. I use it with Magic Tabs.
At first, I feared that this would conflict with my other Javascript plugins, a problem that is apparently not uncommon. So far, it's been working great, with no conflicts.
Even though the author has responded quickly to my problems his own site's pages load very slowly. He needs to fix this.

This is the only module or plugin I can find that can display PARTS OF AN ARTICLE. In other words, each tab reveals a portion of a single article. Other tabbed displays show Modules or entire Articles. I do not need to create an separate Module for every tab, or a separate Article for every tab.
--There are a dozen different ways to reveal the Tab contents: slide up, down, dissolve, switched, stacked, etc.
--Not mentioned by the developer: If you create more tabs than will fit in a row inside your content, the plug-in automatically wraps them around, so you have 2 rows of tabs.
--You can place a tabbed section ANYWHERE WITHIN AN ARTICLE.
--It plays nice with others. So far, it has not conflicted with any other java on my site.--The author responds before the end of the day to any questions posted to the plugin's forum page.
One complaint: the publisher's site is extremely slow. It takes as long as a minute for each page to display. This does not build confidence in the programmer's skills.