It’s hard to overstate the difference a good dryer can make as compared to the drugstore brands. I have the Sedu and the almost as good for a lot less money BabyLiss. Elchim is another that is a very good value. They really do dry in half the time, with far less effort and salon type results. The texture and shine are noticeably different. I barely need to go over it a second time or with a flat iron as compared to drugstore brands.
Other advantages of the more expensive dryers are they may be more reliable and long lasting, quieter and lighter weight. I never travel without my own dryer any more.