The benefits far outweigh the disadvantages of using a real estate agent for selling or buying property.
1. An agent has a much more thorough knowledge of the market, therefore should be able to price listings appropriately, as well as give advice on staging, etc.
2. An agent has a much larger arsenal with regards to contacts and marketing a home.
3. An agent has experience with negotiations, hopefully resulting in a better price for you, whether as a buyer or seller.
4. If you're selling, using an agent allows you to be free to do life normally, instead of having to be home for all showings, take care of paperwork, getting advertising and marketing done, and generally frees up a lot of time. As my company puts it, "We make it worry free". Stress level is very important when selling a home.
This is just a start, I'm sure more will get added. Remember that no 2 agents are created equally, we all have different business models, personalities, and so on. Find one that you feel meets your needs most closely. Also, if you are a buyer, most of the time you are not paying a fee directly to your agent, the seller is, so that's one less thing to worry about. Good luck to you, I hope this has helped!