そう (sou) - (N5 - N4) - Both げ (ge) and そう (sou) express the speaker's impression or hearsay. However, そう (sou) is more commonly used and is neutral in its tone, while げ (ge) adds a more subjective or personal opinion.
と思う (to omou) - (N5 - N4) - げ (ge) and と思う (to omou) both express the speaker's impression or opinion. However, と思う (to omou) is more direct and explicitly states the speaker's thoughts, while げ (ge) adds a more indirect or speculative tone.
ように思う (you ni omou) - (N3) - げ (ge) and ように思う (you ni omou) both express the speaker's impression or opinion. However, ように思う (you ni omou) is used when the speaker's impression is based on a wish or hope, while げ (ge) adds a more general subjective or speculative tone.