There are plenty of advantages to hiring a local electrical contractor who is not part of any agency or organization. It is best to find out the local electricians online, through people you know, and through a local directory of electricians.
You need to take some time to research credentials so that you can find the best electrician for the job. Once you find a list you can compare the electricians and can compare to a big corporate agency to see what is best.
A local electrical contractor can decide how much to charge while an agency may have set prices and no way to bargain it down. You can look at multiple electricians and find out who is willing to offer you the best price for the job. Some electricians may be willing to bargain with you as they will be happy to have your business if the business is slow.
Which might be with the economy. Consider multiple ones as price may be different due to different ways of doing the job Sometimes you might have to pay a little more for services but it may be worth it depending upon the electrician's experience.
The next advantage of hiring a local electrical contractor is that they are more than likely more experienced than an agency. Considering that low-level electricians or electricians with little experience can work in a corporate company under others but are not able to work on their own. It is still important to research the credentials of electricians to make sure they have the experience you are looking for and also ask them what they do best in terms of their electrical work.
The last but not least advantage is knowing that a local electrical contractor should be licensed. Make sure to research the electrician to make sure their credentials match up with what they should have. A corporation can have people that are not licensed working as apprentices.