Even tho I feel it is better to count encounters for the purposes of players leveling, I still use creature rating as a DM to estimate a level appropriate combat encounter.
I can determine after the fact whether a standard encounter really is standard. If it takes the players a standard amount of effort, it counts as 1 encounter. If it turns out to be trivial, it is only worth 1/2 an encounter. And if it turns out to be difficult, 1 and a 1/2 encounters. An ingeniiius solution might get an extra 1/2 encounter bonus.