It even messed up our server configuration by overriding our PHP configuration (it sets PHP error_reporting to it's own reporting level and never reverts). This last one is enough to make a Joomla developer go mad, let alone a poor Joomla user which has no idea why his site breaks down randomly.
The person who wrote this, apparently doesn't know much about HTML either. It's a terrible mess.
This error_reporting is probably part of the component (mentioning from memory), not the module, but it's the same company.
Let's mention templating. Nope, there isn't any support. Joomla coding standards, not present.
The WORST part though is that they insert a link back to their site, trying to use your site as a search engine ranking boost for themselves.
Avoid at all costs.
We're already lamenting our lost time/costs because of this selection.
I'd say avoid the RSMonials component aswell, which strangely is not listed on JED (they got the extension removed and these parts of it were mistakenly left here?)
RSMonials is listed in JED. Here is the link: http://extensions.joomla.org/extensions/contacts-and-feedback/testimonials-a-suggestions/7590
XIUS is a very well written and to the point extension. It does exactly what it says it does and above all it is very extensible (if you read through the code) and above all it's templates are easily overridden.
One star subtracted because of the terrible use of English and the lack of any meaningful documentation whatsoever.
Moderately easy to use (30 minutes toying around to discover all it's features) with all the abilities I was ever hoping to find, and then some.
I will be using this one quite a lot :)