I'm wondering, what is that ICO agency do for ICO-campaigne? Is it like a marketing unit or they also provide legal support? And token sale - do they manage technical side of the question? How do you choose a good one? Have you ever worked with any?
Depends on the agency. Basically it is a ICO Marketing agency. But some can also offer various other services, such as legal support or technical development.
Take a look at the services section and find some respectable for further communication.