The DRA is a very good tool for diagnosing reading difficulties in struggling readers, but it is time consuming, and the higher levels involve a lot of writing. I have used, and sometimes still used the DRA kit, but only for very specific purposes.
The Sisters talk about the Fountas and Pinnell BAS kit and its value. We started using it at my school last year, and I feel very comfortable with the results I get. It gives important accuracy and comprehension information, as well as a good scale for fluency. I'm not sure what level you teach, but if you're on "the early end", the BAS kit also comes with a pre-reading assessment.
I also like the assessment books in the F & P kit over the DRA kit.