Hi - Acton is a great place to live (I used to live in Burbank). Commute isn't too bad either. Everyone who lives up here basically works down the hill. Morning commute can be pretty bad if you leave between 5:30-7:00 AM, ride home isn't as bad. If you can get out before 5:30 you will be fine, or start later in the morning. Any later and it can really back up in Santa Clarita. Easier to drive than it is to take the train. I've heard it's not very reliable. I commute to Pasadena but I take Angeles Crest over the mountain. That wouldn't work to Burbank. Commute is 50 minutes, beautiful drive, no traffic. There are a lot of vanpools and carpool commuters you could hook up with.
Acton to Burbank with no traffic - 40-45 minutes. Acton to Burbank with traffic... Anywhere from 50 mins to 3 hours if it's really bad with multiple accidents and rain. Might as well stay home and telecommute!
Don't want to discourage you, it's quite doable and you will love Acton.