Handful of cards tested on Pi2 Raspian, sorted slowest to fastest:

**Toshiba 16GB Class 4 (took several hours to complete)**

Block Size 4k Write 0.907227 Rewrite 0.953125 Read 2.81543 Reread 2.89648 Random Read 2.375 Random Write 0.00390625

Block Size 512k Write 4.40723 Rewrite 4.21582 Read 17.5498 Reread 17.458 Random Read 17.4053 Random Write 0.569336

**Kingston 8GB Class 4 (took several hours to complete)**
Block Size 4k Write 0.930664 Rewrite 0.842773 Read 2.74707 Reread 2.93848 Random Read 1.97363 Random Write 0.00878906

Block Size 512k Write 6.87012 Rewrite 6.42285 Read 13.6182 Reread 13.6143 Random Read 13.5264 Random Write 1.16113

**Sandisk 32GB Class 4**
Block Size 4k Write 0.988281 Rewrite 1.11816 Read 3.53125 Reread 3.57715 Random Read 2.72266 Random Write 0.277344

Block Size 512k Write 4.55566 Rewrite 4.41309 Read 10.3506 Reread 11.1279 Random Read 11.1279 Random Write 1.22461

**Micro Center 16GB Class 10**
Block Size 4k Write 1.37988 Rewrite 1.50391 Read 3.61328 Reread 4.61523 Random Read 3.74121 Random Write 0.415039

Block Size 512k Write 8.64258 Rewrite 9.28809 Read 18.2686 Reread 18.2666 Random Read 18.1992 Random Write 1.21094

**PNY 16GB Class 10 UHS-1**
Block Size 4k Write 1.54004 Rewrite 1.59473 Read 4.89941 Reread 5.30859 Random Read 4.42969 Random Write 0.993164

Block Size 512k Write 7.12402 Rewrite 6.875 Read 17.0186 Reread 15.8545 Random Read 18.4717 Random Write 7.33398

**Sandisk Ultra uhs1 32GB**
Block Size 4k Write 1.30371 Rewrite 1.36035 Read 6.18164 Reread 6.17871 Random Read 4.7666 Random Write 0.790039

Block Size 512k Write 13.1904 Rewrite 13.249 Read 18.5205 Reread 18.5244 Random Read 18.3779 Random Write 2.5293

**Samsung 16GB Class 6 ** http://www.samsung.com/us/computer/memo ... -MS16DA/AM
Block Size 4k Write 1.47266 Rewrite 1.68359 Read 5.16699 Reread 5.07031 Random Read 5.06934 Random Write 1.63477

Block Size 512k Write 16.9814 Rewrite 17.1748 Read 17.8906 Reread 17.8857 Random Read 17.877 Random Write 17.1445

**Samsung Pro 16GB Class 10 uhs1 **(ran on B+ with other stuff running)

Block Size 4k Write 1.32227 Rewrite 1.63574 Read 5.12402 Reread 5.11719 Random Read 5.02441 Random Write 1.54492

Block Size 512k Write 17.04 Rewrite 17.1963 Read 17.9385 Reread 17.9248 Random Read 17.9297 Random Write 17.2061

**Samsung Pro 16GB Class 10 uhs1** (on Pi2. this time with nothing else running)

Block Size 4k Write 1.9209 Rewrite 1.92871 Read 7.33496 Reread 7.36914 Random Read 7.33008 Random Write 2.24219

Block Size 512k Write 17.2217 Rewrite 17.5508 Read 18.3584 Reread 18.3623 Random Read 18.3633 Random Write 17.4951

**Samsung Pro 32GB Class 10 uhs1**
Block Size 4k Write 2.13184 Rewrite 1.89453 Read 7.29492 Reread 7.29688 Random Read 7.25195 Random Write 1.38965

Block Size 512k Write 17.6465 Rewrite 17.6377 Read 18.3613 Reread 18.3633 Random Read 18.3604 Random Write 17.7373