Skinny Mobile updated their roaming rates to beat Spark's. If you are only going on holiday for a short trip, the new packs can make more sense than getting a local SIM, particularly if we're talking about Japan, SKorea, USA and Canada which have pretty high upstart SIM costs. Plus there's also the niceness of being able to keep your NZ number while overseas. There's no mention who the roaming partners are, but it would be reasonable to assume it's the same as Spark's partners.
* 3 Day Add-On: 100 Mins/100 Texts/500MB - $10
7 Day Add-On: 1GB - $15
7 Day Add-On: 200 Mins/200 Texts /1GB - $20
Australia, Argentina, Canada, Puerto Rico, USA, US Virgin Island, France, Germany, Ireland, Italy, Spain, UK, China, Hong Kong, Indonesia, Japan, Malaysia, Philippines, Saudi Arabia, Singapore, South Korea, Taiwan, Thailand, UAE, Fiji, Nauru, Papua New Guinea, Samoa, Tonga, Vanuatu, India, Vietnam, American Samoa, Qatar, Switzerland, South Africa.
Let's hope 2Degrees takes the fight to Skinny/Spark, since their roaming plans are now pretty uncompetitive now.