It's really hit or miss, but in my experience, it helped dramatically. The premise is basically that if your ISP or some intermediate service (ie Akamai's DDoS protection) is screwing with how traffic is routed to the servers, causing your ping to be abnormally high, a VPN can potentially force your traffic to take a more optimal route to the servers.
A VPN will only help if your ping is in any way affected by sub-optimal routing, and only if the impact is high enough. If your ISP has good routing, or you're not affected by intermediate services screwing with traffic routing, a VPN will not help, and may in fact hurt your ping as it's introducing another point of failure. If the impact isn't that high (ie your ISP has decent routing that could be better, but doesn't hurt your ping that much), you may find your ping being slightly higher due to the added overhead of the VPN.
In my experience, though, it helped a ton. From around October last year until September/October this year, Oceanic users were pushed into a new Akamai data center located in Singapore, which added 100+ms onto our ping. A lot of users found success in using VPN's such as WTFast, ExitLag, or Mudfish, which would bypass the Singapore data center, and drop our traffic off directly in the US, which shaved most of the added ping off.
This was really hit or miss, though, as some users didn't find much success in using these VPN's, and a few even found that it increased their ping. Generally, though, it did seem to help most users, and it certainly helped me.
nafensoriel wrote: »Do a traceroute to the server.
If the route looks really wonky then a VPN might help.
If the route is very logical it probably wont.
To define a wonky route there was a really bad problem with ISPs in the city of Calgary in Canada where they would get routed through Chicago to communicate with California. In this case, a VPN drastically reduced latency because it halved the distance to communicate.
From NZ to EU you are going to not get much better than 320-350 ms due to distance. However a VPN can help with routing stability so might actually cut a little bit off your ping.
It's definitely worth a try, but don't expect a great drop, especially if your routing with your ISP is already optimal or close to it.
Also to consider is the direction of your routing. If you are being routed through Asia to Europe then congestion could be an issue,. if so then using a VPN node in the USA could enforce the route across the pacific where there is less traffic.
Good luck. I would be interested in your results.