The sandisk extreme 16gb card is $10.00 more but is rated 30mb/sec..if using for HD video or continuous photo should be worth the extra

If the device your using the card in cant write that fast then theres no point in buying a "faster" card..

^ except that whatever you write to it, you'll probably want to read the data off too which also tends to be faster, and odds are you'll wear out the device before the card with the next device potentially writing faster.

Question is, what's that worth to you with flash getting cheaper every year and at $10 more it's over 50% higher cost.