I know this thread is old, but I'm going to add my comments anyway. I've started a masters degree 30 years after doing my undergrad degree. I've been working for the last 15 years or so as a bid writer, working to deadlines every day and often doing overtime. The masters degree I'm doing is in social policy. It's much harder than work, and I'd say it's much harder than my undergrad studies. The difference is the amount of reading you have to do, and perhaps my own desire to really understand everything (I think I'm less content at staying baffled than I was when an undergrad). I have two assessments associated with the courses I'm doing this term (plus a voluntary practice essay). One assessment is a 5000 word essay where we're expected to have 15-20 references cited. The other is a write up of a research methodology (no actual research needed) and for that we've been told that a good submission will cite 20-30 references. For this reason it really is in a different league to my degree.
I agree with others, you will have no social life and it will be an intense slog. I am enjoying the course very much, but truly I am currently dismayed at the intensity of it. It's probably because I'm already employable and my study is out of interest and to possibly change careers, but that's not essential that this bothers me. I guess for many, it's good to get it over and done with in a year. However if I had more money, I'd consider moving to a part time course so I could have some work/life balance, learn more in depth and do some housework from time to time!