I've never used KV but for what I have hear from others in the forum I would never recommend it.
I use railwire and know few people who use railwire.
You can go for railwire, as it has decent international speeds and routes.
Thier NOC support team works 24/7 and if you any issues with PS4 nat type, they'll help you and you don't have to pay anything extra for that.