If you work traditional hours, the Metrolink train would be nicer and faster than the bus, but, would be expensive for such a short trip. It gets from Glendale station to Union station in about 15 minutes, and from there the Red line would get you downtown. $100 a month.
Metrolink :: Welcome
Haven't tried the buses in that part of town, but, a bus is a bus. Doable, slow, boring. The 794 bus is the express bus (meaning that it has fewer stops). According to its schedule, the commute from downtown Burbank to downtown LA takes about an hour.