I will point out why this testing is flawed:
1. It looks like you are tracerouting from US back to NZ. Routing is not always the same both ways, so this might not mean much for a connection initiated from NZ.
That's probably why ihug had lower latency. Connects initiated in NZ could take a different path, but it's more common to have assymetric traffic, with one path going via AU and one via Hawaii then to depend on which end initiates.
2. Who's to say that the www is on their network core or that it has any bearing on residential customer traffic routes
True - but I don't have the IP's of any residential connections.
A better to pick a server in the US - or several - and trace routes from residential connections on each ISP with good local performance.
Let's also be mindful that not all ISPs have interconnects everywhere, so the best path to two servers in LA might be very different.
That'd mean having residential connections on multiple ISP's, which I don't have.
Although ISP's don't have interconnects everywhere this is coresite/any2ix, which is one of the major interconnects between NZ and the world. Although one little issue is that any2ix is located in both southern and northern california, and vocus are only peering in northern california. Which is why the 2nd hop shows pings of just under 9 msec. Connectivity to facebook for instance may be a little better, as it is also in northern california.
But basically the concern of higher pings due to going via Australia is already happening to some extent. And could happen more.
Globalgateway can have high pings sometimes too. But don't show an australian hop.
traceroute to www.trademe.co.nz (184.108.40.206), 64 hops max, 40 byte packets
1 220.127.116.11 (18.104.22.168) 0.930 ms 0.887 ms 0.962 ms
2 ge0-15.as01.lax07.mzima.net (22.214.171.124) 0.550 ms 0.527 ms 0.522 ms
3 126.96.36.199 (188.8.131.52) 17.210 ms 17.496 ms 17.805 ms
4 f0-0.pabr1.netgate.net.nz (184.108.40.206) 9.116 ms 9.31 ms 9.26 ms
5 ae0.sjbr2.global-gateway.net.nz (220.127.116.11) 9.603 ms 9.434 ms 9.458 ms
6 so5-0-2.akbr4.global-gateway.net.nz (18.104.22.168) 166.1 ms 162.230 ms 166.113 ms
7 ae5-2.akbr5.global-gateway.net.nz (22.214.171.124) 166.488 ms 166.486 ms 166.492 ms
8 trademe-int.akbr5.global-gateway.net.nz (126.96.36.199) 167.839 ms 167.727 ms 167.404 ms
9 www.trademe.co.nz (188.8.131.52) 166.815 ms 158.339 ms 158.434 ms
Mzima is a pretty major tier 2 transit provider. And has a suboptimal path too.