Well nothing a is a match for Gjallarhorn obviously, but that doesn't mean it's not a really good weapon. Thubderlord absolutely destroys on this weekd nightfall. As for PvP, it's hard to use any MG when everyone is running around with rockets with G&H
Yeah i love my thunderlord is my fav of all heavys, but i use it in fun situation is hard to use in more serious ones. It should have more bullets or overpenetratiion
Over penetration would definitely help. It's good against mobs or when arc burn is active. Depending on how hard the Gjallarhorn nerf is though, I'm fully prepared to use a thunderlord as my main exotic heavy.