SPS - not overrated at all. I don't have to worry about cake sliding, I don't worry about cake collapsing, I don't have to stack onsite and I don't worry about customers coming in to pick up their own tiered cakes, usually party cakes. I give them driving advice but I hope things make it okay, but I know that a dowel isn't going to shift or a cake slide off.
I HATED making tiered cakes before SPS and now, we often deliver 5 tiered cakes already stacked. I like to decorate after cakes are stacked most of the time and with SPS, it's not a problem for me to stack, decorate and then deliver.
You can never go wrong with SPS. As far as costing more, I charge my customers for it and no one has ever complained.