I have hired freelancers before but never went in for a virtual agent therefore here was my experience-
1- $300/Month = Extremely Low Quality of Work PERIOD.
2- Massive amount of training would be needed...You just can't hire a person and expect him/her to perform the way you expect them to.
3- Constant supervision is required...You just can't delegate and task and think it will be done on time.
4- It's not easy to fire them...And they can cause extreme damage. One of my agents deleted all the blog posts I asked her to make after I said she wasn't doing the task the way I asked her to do it.
5- There is always a big difference between what they say they can do and what they can actually do. Therefore test them before you hire them.
6- There is absolutely no way that an agent will make you automatic money within weeks of hiring. This is just not practically possible for someone working for $300-800 a month unless they have special skills and the one's who do don't come that cheap.
1- Always hire an agent on a 2 week trial basis where you will pay them only so much to test their skills. Let them know that you will only hire once you are satisfied with their work.
2- Testimonials don't really count that much specially on freelancing sites. I saw some agencies with thousands of great testimonials but crappy work.
3- Always tell them exactly what you want them to do...If you them to submit your link to directories then give them a list to submit to. The more specific you are the better.
4- Never give an agent your credit card details, passwords etc too early. They can cause some serious damage if you decide to fire them at some point.
5- Have a certain set of tasks for a month and pay them according to the completion of tasks. That way they will be highly motivated to do the job right.
6- You won't find real good quality at $500/month therefore don't go with the flow and do your own personal research. Good agents charge more just like good writers charge more for a good quality article.
7- Always outsource to big outsourcing firms as they have a proper team with a team leader who will make sure your tasks are performed in the right manner. This won't come cheap but will ensure best work possible.