For me , specifically the ability to have a certain number of several categories of attendees and set limits based on those numbers was critical. For all other extensions I found if I wished to have equal number of guys and girls I would have to set up 2 separate events which was very confusing to the attendees. This functionality would also work for people who have premium seating, adults/children's tickets, or many other areas.
I cannot say enough about the support. Every question I have asked has been answered in a very timely fashion and the extension has been able to be put in place in a very short period of time for me. I highly recommend giving them a shot if you are looking for an event management extension.