It's not at all uncommon to find multiple modules that provide basically the same functionality. For instance, there are many SPAM control modules that offer extremely similar functionality (e.g., Spamicide and Hidden CAPTCHA). And there are lots of Taxonomy modules that do similar things. So when multiple modules meet my requirements, how should I choose which one to use?
Personally I do a few basic checks before digging deeper.
- How many reported installs? (about the same in your example modules).
- How long since last update to module? (Spamicide is 5 days ago (from today))
- How many open issues?
- Who is the developer? (Have they worked on other modules that I use, etc).
Then you can start digging into integration, if I where looking for an inline image management tool I personally would choose something that takes advantage of other modules instead of rolling it's own solutions, something that is features exportable, etc.
I check the number of installs, the number of developers.
Then I'll look through the open issues/bugs and use my judgement to decide if I'd ship a problem with those issues. The responses to issues by the developers are very important to me in this process.
The number of open issues is misleading because all too often the issues aren't actually issues at all.
Finally I'll probably look at the source;
I also won't touch anything that doesn't or isn't going to have a D7 version. This may be a crude unfair metric, but it works for me, sofar... Open to persuasion that I'm wrong about this one.
Generally, in addition to the number of installs, how quickly after a new release of Drupal does this module get updated. This tells me how quick the devs are, and that also tells me how quick they will be to address any serious issue.