I can recommend against them. I used one that was reliable and my character was leveled to 50 but he sucked !@#$%^&*. No traits were worked on, no class quests were done, in fact tons of quests were skipped, including EPIC ones. I had book 6 done and that was it. I used this character to PL my other ones eventually, and even though I kept him I use him very little now and have since leveled up a new version of him on my own.
I guess if you want to use them as a power-leveling tool then they are great, but anything else, and you have some work to do. I used
www.game-sale.com. They have good prices and even will work out with you if you want your character during certain times, etc. Make sure you are doing this with a NEW character that no one knows. I got a few tells after they finished and it was weird. Good luck whatever you decide, but if I had it to do over again, I would have just 2 boxed my way.