I'm using the app and I can definitely tell that it is one of the few gems out there for keeping your mac apps up to date.
What I also like about that app is the behind the scenes infrastructure and their support. The caring of the company about the app stands out and that made me want to encourage others to use this app as well by having it on my must-have apps list that I recommend to both new and old mac users.
About the price, I have to agree that maybe the price tag of $15 seems a bit high for the purpose of the app since it is a functionality that most of the apps include and theoretically speaking you don't actually need a third-party app to update your apps.
The value the app provides isn't the fact that it can detect outdated apps and allow you to update them all together (or selectively), it's the time that it saves you by manually opening your apps and checking for updates.
For some that type of labour maybe it a joyful process, those individuals don't actually need the paid licence, the free licence can cover their needs by allowing them to view the outdated apps and launch them directly from within MacUpdater (also update up to 10 apps from within MacUpdater).
For other people who might be either busier or are not fond of manually checking for updates or they might value that their time costs more, therefore they try to save as much as possible of their time, the price tag for $15 for 4 macs (for standard edition) sound more than fair. MacUpdater infrastructure maintaining a database with over 100k apps and daily labour is put to keep the database up to date, without the database the app itself won't work, so, again, I tend to believe that in that scope the price is fair.
Lastly, the company offers
discounts for students and individuals living in countries outside of the
40 wealthiest countries of the world, and as for their statement
"just contact us and we will work something out", I can assure you that it holds true as I have first-hand experience for that.
PS: The reason I'm writing that is as a token of appreciation to the developer with whom I came in contact (for the statement I mentioned earlier) and
"we worked something out". It's not a paid advertisement in any form.