Smaller particle size increases efficacy of inhaled steroids.
Some reps will suggest better efficacy with their inhalers over others because of smaller or “micronized” particle sizes.
You may hear this with the revised formulations of beclomethasone (Qvar) and flunisolide (Aerospan HFA)...or the new Alvesco (ciclesonide) inhaler. These all come in solutions.
All other inhaled steroids come as either an MDI in suspension...or a dry powder inhaler (Flovent Diskus, etc).