With so many SDHC memory cards on the market, it can difficult to truly determine which one is the fastest in real-world situations. Based on this comparison, price is not necessarily the best indicator of performance.
If you hope on over to Gizmodo, Curtis Walker put no fewer than nine of these high capacity, postage stamp-sized cards through a couple of tests: transferring files to/from a computer and taking high resolution photos with a Nikon DSLR.
In the end, Curtis concludes that the best Class 4 SDHC is easily the SanDisk Ultra II, but when it comes to Class 6, the picture is a little murkier with a close battle between the cards offered by ATP and Lexar. In the end, he gives the title to Lexar, but mentions that the budget-minded Dane-Elec SDHC card is an excellent performance bang for your buck.