Simple and easy gallery. The layout is plain and basic - there are fancier galleries out their for free - but SIG allows you multiple galleries within your images directory, and you can use the Joomla media manager to upload the photos.
So I'm being honest here and giving this an average rating. (sick of people giving everything an excellent rating - it wastes everyones time).
What really bugs me is all the advertising you need to wade through to see a the real demo of this extension. Most of the stuff you need to pay for. I've looked at this extension before and left it alone after getting peeved off with the adds and high level marketing.