The way I understand it, there are 2 ways that lowerping uses to lower your ping:

1) QoS - Quality of Service, tunneling packets inherently get a higher priority through networks.

2) Predefined lower latency route -- usually, not high bandwidth, but WoW isn't high bandwidth.

Doing this, will definitely improve your latency just because of (1), but it will not do anything for (2). Thus, using this, I believe, will definitely help, but lowerping will give slightly better results. Considering that you eliminate your risk of a ban, I'd say this is a better way to go about it. However, I'll have to wait for another day when I don't log in for a day or so before I switch my method or I may set off bot alarms due to rapid IP change.