Many of these are simply excess wine that couldn't be sold as straight sauvignon so, instead, they've put it in a sparkling bottle and carbonated it. It's the equivalent of a fart in a bottle, really, and about as charming.
Happily, there are plenty of really nice bubblies out there that are well-made and taste lovely. And buying them needn't break the bank. It's perfectly possible to get a good sparkling wine for less than $20 and often less than $15 in supermarkets.
It's versatile, too. It matches well with a wide variety of food, from fish to desserts. And it comes in a range of sweetness, from bone-dry to lusciously sweet. The sweeter styles, often from muscat grapes, can be fantastic wines and while this may sound either very naive or downright ignorant, the humble Bernadino Spumante is a cracker of a wine that you can pick up for next to nothing.
At the other end of the scale it's hard to beat Champagne. Certainly there are spectacular local sparklers, but there is something magical about good Champagne that can never be replicated anywhere else. There are some really good deals on Champagne coming up, too, as we head towards Christmas, so watch out for them at your local liquor retailer.