Both of these services are dangerous for app developers because they offer simple, one-tap installs of pirated apps and do not require that devices have been jailbroken in order to do so. This is an enormous problem, as it opens up the arena for their use from the relatively small fraction of users with jailbroken devices — as was the case with Installous — to any unscrupulous users of iPhones and iPads.
Don’t steal from developers people. Bad karma shit will come back on you.