The most important things to look for in an attorney are experience, reputation and dedication. It won't matter where your attorney is from if they are lacking in these areas. For the pros and cons, let's assume that whomever you might consider possesses these talents abundantly.
LOCAL ATTORNEY PROS There is often a benefit to having someone that knows the local terrain. They may know the filing quirks, or the habits of certain courtrooms. They may have even thrown a few back with your prosecutor the night before... which is not to suggest that the State will likely alter their plea offer because they know the attorney. However, it is frequently helpful to have attorneys with access or a good rapport with the State to facilitate resolving a case. Former prosecutors often make good defense attorneys, and this is one of the reasons. Additionally, a local attorney may have a good reputation with the local judges or prosecutors that may serve them well in court. There may also be residual benefits such as ease of meeting with a local attorney, as opposed to phone conferences for an out of towner. Knowledge of the local judges may give the attorney a better insight on possible rulings and sentencing as well. There are many reasons to try to stay local.
LOCAL ATTORNEY CONS Sometimes people think that a local attorney is more likely to sell them out to maintain a relationship with the State, but that has not been my experience. If an attorney is not aggressively representing a client, it is more likely their approach to the law than a deference to the other side. (You could just as easily end up with a non-aggressive out of town attorney, too.) You may need to look out of town if your issue is something extremely specialized and complex. It may be difficult to find an attorney with experience in a specific area, (such as taxes, investments, land use or maritime law,) who also is a top defense attorney without broadening your search. Or, you can seek the best of both worlds, if a local attorney is willing to bring in expert help in the specialized area of the law that is required on a case, although that can be as expensive as bringing in an out of towner as the lead attorney.
SUMMATION There are many benefits to using a local lawyer. The main thing to be concerned about is usually not where the attorney comes from, but whether they are the right fit for you and your case. Speak to several attorneys if you can, and speak to other people and investigate through sites like AVVO.com to find out about reputation and experience. And try not to let price decide, but be careful of outliers... attorneys that charge much more or much less than their competitors.