there's only so much good cork to go around. NZ winemakers kept getting sold the crap cork, so they've pushed for screwcaps.
you can find even premium NZ and Australian wines in screwcaps these days -- $60 for a top Hawkes Bay red blend built to age for 5 to 10 years. Some top NZ winemakers do all their wines in screwcap -- it reduces corkage and allows for more even ageing/oxidation over the life of the wine.
so the Savvie you tried was exactly as the winemaker intended it with no infection from cork-born chemicals. it takes some of the risk out of wine-buying.
i haven't tried the Kim Crawford -- not a fan of his wines -- but other really good Marlborough Sauvignon Blancs are St Clair, Huia, Isabel, Spy Valley, Astrolabe, . . . etc. etc. i reckon they're all best drunk around 12 months after bottling, and on a hot afternoon around a barbecue. they've generally got high acidity and are pretty tart -- sometimes they have a tomato leaf pong to them (especially if they come from the Awatere Valley) or smell a bit like freshly cut grass or asparagus.
also, if you like Marlborough sauvignon blancs, you'd probably like Martinborough sauvignon blancs -- Palliser Estate exports to the States, and is usually a knockout. Hawkes Bay sauvignon blancs tend to be less acidic and more tropical fruit-flavoured.
this link has reviews of loads of NZ sauvignon blanc, and there's probably a discussion about screwcaps on the site somewhere: