There are several great Virtuoso agents here on FT.

Here are a couple of posts that list a few:
http://www.flyertalk.com/forum/11707310-post55.html
http://www.flyertalk.com/forum/11355793-post14.html

While it's hard for me to give an unbiased opinion here, I absolutely see the value it working with an agent. The level of service that you receive will vary from agent to agent, but the best will help you with all aspects of planning (including flight schedules and upgrades). Another significant benefit of working with a great agent is that he can call ahead to the properties to have you "VIP"ed - basically any agent that's worth anything should have contacts throughtout the industry that he can call on for any specific requests (or just to make sure your stay goes smoothly).

Furthermore, you have nothing to lose (unless you are working with an agent that charges a fee). You should be getting the same or better prices with the bonus of added amenities and expert planning help.