For larger areas you get better coverage with a air brush. It is ok to hand brush small items but you would not get very good results if you hand brushed an entire model. The air brush is the only way to go when doing large items.
Metalizers are so thin that a brush will soak up more than you would be able to use.
Berny
Phormer Phantom Phixer
On the bench
TF-102A Delta Dagger, 32nd FIS, 54-1370, 1/48 scale. Monogram Pro Modeler with C&H conversion.
Revell F-4E Phantom II 33rd TFW, 58th TFS, 69-260, 1/32 scale.
Tamiya F-4D Phantom II, 13th TFS, 66-8711, 1/32 scale. F-4 Phantom Group Build.