Successful by what definition? Or just do the owners "like" the aquarium?
My (6+ year) experience has been excellent. Solidly built, well engineered, quality components. Can grow any type of reef you can imagine.
Maintenance is fairly easy. Being a rear sump AIO, it lacks some of the flexibility of an under cabinet sump style tank. But all types of add on equipment & mods are still possible. It can even be outfitted with an under cabinet sump/refugium if you like.
It can be set up & a cycle started in a day without ordering custom tanks, drilling, plumbing & other stuff and you can avoid the mistakes often made DIY. (But I understand that aspect is actually more fun than keeping the animals themselves for some folks) I like the minimalistic clean look & the hood design is really useful.
With all that said my next tank upgrade will be an under cabinet style, perhaps the Red Sea Reefer series.