Meowmere does better in smaller rooms and on long distances. Sword itself deals high base damage and can reach more damage per hit than Sniper Rifle which transforms into dps due to its speed. Star Wrath can wreck in opened spaces, especially when the target is bigger. With proper gear you can reach high speed ( around 9 use time ) and around 200 damage, which gives 400 per star. So you basically deal 1000-1200 to enemies per swing, but it is mostly effective against crowds of them, when you don't want to aim or against huge hitboxes. I prefer the latter, since it's a rather serious weapon and I like its special effect. But if I was to tell which sword is my most favourite in the whole game, Terra Blade would be there.
Voting for SW.