I have to say, Installous was actually a really impressive app for what it was.
It was literally as simple to use as the original App Store, which was incredible. I've never seen that kind of excellent design in an app designed for piracy. It seriously "just worked" in the same way that you'd expect any iOS app to work: you searched for an app, clicked install, it'd take you to a mirror (usually on a site like Mediafire), download it in the background, and install. The interface had a shocking amount of polish, too.
I can't really argue, as a developer, that it's a shame that development has stopped on it, but still - there must be a lot of smart developer talent in that group that will hopefully be put to better use now :)