Vectors prime is better in my opinion because
1:equal deposition
2:equal falloff/min damage range
3:fire rate is quicker
4:(this is a big one) can empty its magazine quicker than the lanka's charge up(2.76rounds per second)
5:more fun to play with arch wings on poe(feel free to comment on this)
6:no charge up and can be fired instantly
7:is a hit-scan compared to lanka's charge up(works really well for stealth with banshee passive suppress or Loki invisibility augment; hushed invisibility)
8:easier zoom mechanics
9:best sniper for most categories (as of fandom comparing all sniper weapons)
10:cooler name
11:is a prime (for some reasons prime's are generally the best/better weapon)
12:cooler name and look (snipetron and Lanka are almost indenticle( can't remember spelling(lol)))
Without lanka's charge it has higher base damage
but Lanka has higher damage and elemental(electricity) which is just about all that better