The great Bhartṛhari says thus:
maheśvare vā jagatām adhīśvare janārdane vā jagad-antarātmani ।
ṇa vastubheda-pratipattir-asti me tathā’pi bhaktis-taruṇendu-śekhare ॥-vairāgya-śataka, 84
I do not see any difference between Maheśvara who is the Īśvara of the universe, or Janārdana who is the ātmā of the universe; but still, my devotion is towards Śiva (the form that has the crescent moon as its crest-jewel).