I was actually looking into them as well last night but want to compare them with the many other options available as I only have a limited amount if SP I can afford to delegate out in order not to reduce my support to my followings too insignificant.

As to the term 'agent' which sounds weird to English speakers, the Chinese term for delegation is the same term as an agent. In both cases you are authorising a third party to act on your behalf, so when one google translates the chinese term to English，you get agent and proxy. I imagine agent was used because it's easier to understand than proxy.