Hmmmmmm.. I may look into this.
My own experience, four games on Friday night:
Annie Mid - No lag spikes. Ping went from ~110 to ~80.
Lulu Support - No lag spikes. Ping went from ~115 to ~80.
Lulu Support - No lag spikes. Ping stayed high-ish at ~100. Disconnected for about 90 seconds and I think I had issues with key inputs not registering (although that could just be me). I changed the VPN server I connected to so this might have been the cause.
Janna Support - Turned off WTFast. Iffy latency and stability. Disconnected for around 90 seconds.
Last night was a custom game vs. bots getting a feel for Ahri. 55 ping. I don't think I've ever had a smoother experience.
Will this work for someone who plays on EU Nordic with an average ping of 150-170 per match?
Depends. It doesn't magically reduce your ping. What it does is re-route your traffic. If there's a bad hop being used in your regular connection the program will fix that. If you're getting 150-170 ping due to distance from the server WTFast won't be doing much at all.
Just want to add the service isn't free outside of the 30 day trial. I'll be signing up likely after a few more test runs. $10/month (or less) is worth not having to put up with these issues until Riot sorts out their new network/servers. Signing up should yield even better results, in theory. In the trial you can only select your "start" server (tip: pick the one with the lowest ping) but in the full version you can select both the "start" and "destination" servers which makes the routing even better.
Also, I don't know what to do for mid picks anymore. I seem to be adding more and more to my test list, latest being Ahri. It's going to take me forever to sort this out. Sigh.