I have very good impression from trying this component, however it seems it is not written very well in terms of accessing database. It uses insane number of queries, efectively sucking out my user quota every time I try to use it...
"User 'user.org' has exceeded the 'max_questions' resource (current value: 10000) SQL=SELECT name, value FROM ..."
However, it is possible, that it only does this in combination with "com_opensef" (I do have it installed but I don't use it due to compatibility problems).

Yes, it certainly has a potential, I used it [testing] a month.
But there were serious problems - i.e. today I found some categories *disapeared* and I can't edit categories details anymore - it displays always details of 1 same category nomatter which category I click to...
And I read some frightenning articles about how dangerous RSGallery is in terms of security. It seems it's "leading" unsecure component!
But a good thing is, that there is a development and there were 2 new bugfixes and updates last 2 days (29 July), so maybe some of the topics mentioned was fixed...
BTW I found Zoom Gallery and it seems to be a "different league", it's stunning!