Pros
Obviously one of the best things about Zirtual is that you can work from anywhere, but it's also great that you can choose how many clients you take on, thereby choosing about how many hours you'll be working each month. There are really good support systems in place so that if you're having trouble with a client, you have someone to turn to for help--and they won't think you're any less good at your job for it, since they understand that personality issues can come up in a service like this. The management really makes an effort to be involved with all parts of the company, and there was a nice community feeling despite the fact that most of us never met each other in person. Of course, it's important to stress that your experience with Zirtual depends largely on the clients you have. Some clients do tend to be less respectful or friendly than others, or they'll give you vague or confusing instructions for a task and expect you to get it right. But the management is very aware of these things and involved in working to mediate them--they give great advice on how to humanize yourself to your clients so they don't view you as a task robot, and on how to establish better communication with clients. They're even willing to step in and talk with the client on your behalf if you're having trouble resolving the problem. The great thing is that while this is obviously a customer service based company, the management really stands by their employees instead of just saying that the customer is always right. I always felt like a valued resource within the company, even at times when my clients weren't gushingly appreciative.
Cons
The workload can be inconsistent and erratic, since it's completely up to your clients how much they ask you to do and when--so if you're considering working at Zirtual, make sure your schedule will be okay with this. Sometimes I would go almost 2 weeks without having any tasks from a client, and sometimes I would be getting tasks every day. (Note: this was when I had 3-4 clients, so those long periods of silence are much less likely if you have more). The good news is that you get paid the same regardless of how much your clients have you do, so you don't have to worry about your income suffering when your clients don't need anything. Personally, I stopped working at Zirtual largely because of where I was in my life--I had recently graduated college and I wanted to transition from a part-time virtual job into a full-time in-person job. I also just wanted a change of industry, as I wasn't looking to be involved in the executive/personal assistant business in the long run. For me, even though I really liked the structure and culture of the company, the work itself wasn't something I was looking to do long-term.
