My issue with perception (like other skills) is that I don't want every single player at the table rolling for it. If that is done, I have to up the DC a lot to have some chance of nobody making the roll.
Granted, this is perception not used for surprise. For surprise, everyone gets to roll and you either beat the average DC of the hiding monsters, or you did not.
But when I want them to just notice or know something, I usually ask for a skill roll for the PCs trained in a given skill, perception included. Or in the case of perception, I often have the front 2 or 3 party members roll for it, trained or not at the first moment that the front PCs are able to notice something (it comes into view, or they are about to step on a trap or whatever).
The generic problem of everyone rolling the skill is that someone is bound to roll high and make the DC. If that is the case, why bother rolling the dice at all?