Apparently, researchers at the University of Michigan thought the practice had some merit. They tested the use of saline sprays against the use of what they called "saline irrigation." The only difference between saline irrigation and the neti pot is the tool itself. Rather than a neti pot, saline irrigation is done with the use of a bulb syringe.
Specifically, the researchers randomly assigned 127 people with chronic sinus and nasal problems to either the saline spray or the saline irrigation. They found that the people who used the saline irrigation had less nasal discharge (i.e., snot) and reported fewer symptoms of stuffiness and congestion after 8 weeks than those who used only the saline spray. Their recommendation: nasal irrigation is a useful therapy for nasal and sinus symptoms.
So if you suffer from chronic sinus problems, you may want to add sinus irrigation to your regimen. And if you're into pretty things - there are a lot of lovely neti pots to try. It's not a dainty practice, but it sure saves on Kleenex.