I don't, but for comparison, I would follow the same kind of test that PC magazines use. For example, one magazine might test a groups of drives by writing the same 600MB of mixed files to all the drives and timing the process. If you do the same, you'll get a good idea of how your drive compares.
However, if you want to know exactly what speed the drive is running at during the write process, that might be more difficult. I can't say that there isn't any software that can do that, but I don't know of any.