I too use a vac. It is care and moderation that is needed whether you suck or blow. The danger with suction is allowing the nozzle to form a seal and so dislodge or damage the less robust parts of the innards.
I use a cheap small paintbrush to clean the fan blades and other accumulations, but always under the draft of the vac which nozzle is as close as possible to the scene
Blowing and particularly from an aerosol is expensive and though gentle, will scatter the dust willy nilly. Having said that, it is whatever serves you best.