Drupal CRM Core releases
The fact that the stable release has an unusual version number doesn't mean there is anything wrong with it.

It's just the way they are doing there releases.

If you look at all the crm core releases you can see that the first stable release was 0.9.

I would guess they have done this so that they may be able to get more people using it and fix any issues that arise before having a 1.0 release.

So 1.0 will be the next major release.

Then they use versions 0.91, 0.92, 0.93, ... as the intermediate level releases and for minor releases in between those they use numbers like 0.911, 0.912, 0.913, ....

When choosing a version of any module this would be my advice:

Use the latest stable release.

If you encounter any problems with latest stable then check the issue queue for possible fixes and if you need a patch to apply to latest dev or latest dev has already fixed the problem then try using it.

Remember though to test to make sure everything still works as it should as the dev version may have introduced new issues even though it fixed your previous issue.

Also take a database backup before updating module versions in case the newer version is broken and you need to roll back.

Another reason you might want to use dev would be if you know that there are new features in dev that you want that aren't in the latest stable.

But really, if there is a stable release (especially a recommended stable), don't use the dev version instead of the stable release unless you have a good reason to.

Unusual version numbering is not a good reason.