If it's an authentic 32GB SanDisk card (mine shipped directly from them), it should have a 2 stamped on it.
Class determines the minimum write speed a card must meet for the designated class.
Class 2 = 2 MB/s
Class 4 = 4 MB/s
Class 6 = 6 MB/s
Class 10 = 10 MB/s
Both cards were freshly formatted. Benchmarking tests results from SiSoftware. If I'm reading these results correctly, the Lexar falls short of a Class 10, and the SanDisk could pass for a Class 4. At the price you can get a SanDisk card for, vs. the Lexar, I really question whether the slight lead Lexar has in the combined results really justifies the extra money.