The biggest annoyance I've had with my Brother HL-2170W laser printer is the speed at which data is sent and processed. Printing a one-page Google Maps directions would take minutes. Now, it takes about 15 seconds. What made the difference? Drivers, of course.
When I installed the printer, I selected an appropriate driver from the foomatic database when setting-up CUPS. What I didn't do was to check to see whether there were special Brother drivers which weren't installed by default. It turns out that there are quite a number of special Brother drivers which aren't installed by default. This thread directed me to open up synaptic and search for Brother. Sure enough, there were at least two laser driver packages which I didn't have installed:
P.S. Note that if you don't have a laser Brother printer, you'll need to search through the driver package names to find one that matches your printer. Look for packages that start with "brother-lpr-drivers". The last word in the name gives you a hint of the type of printer it provides support for. In synaptic, you can click on a package name to see the description.