The pay is a complete joke, especially for a job that wants you to have a college degree. They continue to say the company isn't profitable enough for pay raises, and you are not compensated for phone or internet in any way either.
It is INCREDIBLY difficult to balance multiple clients throughout the day, especially with the Harvest timers. I basically had 7 different jobs that I was expected to 'have a little fun with' daily. On top of this, there are mandatory meetings and things you must do for Zirtual every week as well. With this model, small tasks can get forgotten for clients, and the quality of work decreases when you are trying to meet deadlines, etc.
You are limited to how much overhead time you can have, and as someone else mentioned, it's often VERY difficult to fit all of this into a 40 hour work week. With my client load, I was working several hours of overtime a week. A big no to work life balanced. Many stay at home mom's are forced to higher sitters to watch their children during the day because they are so busy. Often times, the sitters are earning more per hour than the Z Mom. Completely not worth it. There is also no real process for placing a ZA to a client. If you have available hours and are in a certain time zone, you will be given a client, regardless of skill set in any given area.
Policies change at Zirtual on a weekly basis, which makes it hard to keep up with what's going on. Clients often ask you to do things outside of Zirtual's scope of service or different than a cut and paste type of task and you have to figure out the pieces yourself. For example, I was handling recruiting for 3 different clients of mine with very different companies.