Starting out in commercials, especially as a freelancer is a little unstable, but once you have worked for 3-4 different studios (and done a decent job) it's quite easy to work consistently. Some studios want to employ you, and then it's like any other job with a steady paycheck. Movies are stable for the length of the movie production, which can be 5 months to 2-3 years, but the likelihood of having to get another job somewhere else after the movie is finished is higher. The pay is usually proportional to the length of the project or contract, lower for longer. If you have a unique specialty however you can charge a lot more, but may get less jobs overall since there isn#t a constant need maybe.
Commercials are fun because you get to try a lot more things and the jobs are not such a long commitment. You learn a lot and learn to be fast. Movies you get to learn less aspects, but much deeper, which is sometimes cool and sometimes a bit boring.
Overall I like both, for different reasons. The hours are better in movies though. I've got a month and a half left on my current movie contract and I have really enjoyed not working overhours and weekends for the last year. After taking some time off, I'll probably aim to do another movie project if possible.
Probably more information than you wanted
