It is interesting to see the differences between the US Ambulance Services. In the UK it is different again. I agree that no adjuct should replace good basic airway management. All to often I see Paramedics going for Gucci kit first before ABC, which is what we have all been trained in regardless of level of training.
BLS
ILS using Oro, Naso, LMA then combitube if needed.
ALS then only if required should intubation be used to secure the airway.
In all honesty if you are trained to intubate why bother with the combitube. Another reason I do not like ths is due to the fact that I would never use one in trauma as you may need to move the patients head for a correct placement. So with this in mind I would either opt of LMA or intubate.