There are advantages to hiring a local electrician who is not part of an agency or corporation versus hiring an electrician that works for a big corporate company. It is best to research local electricians online, through people you know, and through a directory of electricians.
You should take time to research credentials so that you get 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. Consider that there are positives and negatives to choosing either an electrician or a big corporation.
The first advantage is price. A local electrician 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 maybe willing to bargain with you as they will be happy to have your business if business is slow, which it might be with the economy. Consider multiple ones as price may be different due to different ways of doing the job (ie tools they use, etc.) Sometimes you may have to pay a little more for services but it may be worth it depending on the electrician's experience.
The next advantage of hiring a local electrician 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 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 advantage is knowing that a local electrician 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.