I think it's been great to have a simple way to travel overseas and use my voice and data plan there for an added $5 a day on Vodafone in many countries. Keep my number, no fiddling with getting a local SIM card, topping it up, and so forth, it's as easy as it could be (and should be) for a mobile service in 2015. Unfortunately I've since learnt that roaming with my mobile abroad can still be a suboptimal experience.
In Australia, Vodafone's roaming on Telstra and their Australian division's network is unproblematic. I could get fast connections that work almost as well as in New Zealand. That isn't the case everywhere though. In Las Vegas, roaming with Vodafone on AT&T was really quite bad, to the point that I almost went and got a local SIM. Some of it was no doubt due to AT&T's network in Vegas being loaded to the gunwales with connections as Vegas was swamped with visitors.
What made the roaming experience really suck though was the high latency and it seems the connection from my phone was set up as a New Zealand originating one. This meant traffic to and from US servers was bounced via New Zealand, with huge, 550 to over 700 millisecond delay or latency. As a rule of thumb, anything over 250-300ms latency makes applications and web browsers unhappy, making them time out and dropping connections. With over 500ms latency, the internet still works but it's slow, unresponsive and almost not usable. Skype was terrible and I could pretty much forget about streaming video. Even when I apparently got 4G LTE in San Francisco on the return leg, the large, 700ms plus latency meant the connection only managed 0.5 megabits per second down, and 0.3Mbps up.
I asked Vodafone NZ's good and responsive help desk if there was some way to fix this, perhaps by using an Access Point Name (APN) setting for a local gateway, so traffic would go via the US instead. I was told there isn't, and to use the normal "vodafone" APN. The AT&T APNs that I tried would not let me connect.
It's not all negative to have a Kiwi connection abroad, i.e. if we're in countries with heavily censored and filtered internet access like China, bypassing local networks could be handy despite the performance hit. Other than that, routing data locally provides a superior service by far. It can be done, both on 3G and 4G networks that support Local Breakout for data, and Vodafone should pick partner carriers that are able to do just that. Until that's done, the "roam like you're at home" strapline in Vodafone's ads simply may not be true.
