layer = qgis.utils.iface.activeLayer()
initial_features = []
new_features = []
# Get initial count of features
for feat in layer.getFeatures():
    initial_features.append(len([feat]))

print sum(initial_features), "initial features"

# After creating features, use following to subtract new count of features with initial count
for feat in layer.getFeatures():
    new_features.append(len([feat]))

print sum(new_features) - sum(initial_features), "new features"