Depends , but i prefer lothar anyway. It is depends on how i farm. If i farm well , i ll go for lothar , because i will have extra dmg from souls + lothars dmg. When you get lothar , just stand next to hero , and after ulti si done , 3 or 4 hits are enough for kill. With dagger , you dont have dmg and you dont have element of suprise.Above all , with loth you gain MS to cover up that blink distance you would do with dagger.