This is one of those deals where you have to pick your poison. I've been on both sides - getting gigs and hiring bands. I'd rather deal directly with a band if at all possible, mainly because agents have their own agenda (not neccessarilly bad) but isn't always in the best interest of the band. Overpricing, for instance, or bizarro riders. Things the bands sometimes aren't even aware of. At the other end of the spectrum, there are venues that only deal with agents. One call for all their needs, no billions of promo paks and phone calls.
If someone in a band or a close friend can handle the business end, at least you've got control over things. If you need an agent, take extra time to see what is offered, what is expected of you. I remember (way back in another life) I passed up a real gem of a contract with an agent. He could renew indefinitely. Undefined expenses off of gross. Couldn't perform within a 100 mile area for a year if I wanted out of the contract. A lot of stuff that probably wouldn't hold up in court, but the time and expense would drag ya down anyway.
A lot to weigh. Nothing's easy.