We are a California firm seeking patent counsel outside of CA. Is there any advantage to staying local when it comes to finding a patent attorney?
The first legal mentor I had said "Clients will get better results with an average lawyer that they trust, than the top lawyer that they do not trust."
In patent law, the understanding of technical detail will always need to be considered to give good advice. The person with the best technical understanding of the particular patent you are considering would be a good choice. If you are hiring a patent attorney, then you (or an inventor that works for you) should be able to get a pretty good idea about the technical savvy of your patent attorney just by disclosing the invention. The patent attorney should be asking questions about the invention that show his understanding of your technology.
Technical understanding outweighs most other factors. In most cases, communication is greatly simplified by the Internet (web meetings, email, transferring digital pictures, etc.), so it is likely that you will not need to ever meet your patent attorney in person. On the other hand, remember to use a US patent attorney, if you disclose your invention outside of the US before filing a US patent application, you could accidentally run afoul of the law.
Since patent law is federal law, there are not too many differences from one state to the next. Yet, if you are selecting an out of state patent attorney, you will want to consider some of the issues that might be particular to your state. For example, employment law can vary from one state to the next -- so how an employment contract that specifies ownership of intellectual property rights may need to very from one state to the next. Usually, this issues are minor. Also, for example, in patent litigation, the Federal court will follow certain state court rules of evidence, which can impact patent litigation. If you have in-state corporate/litigation counsel and an out-of-state patent attorney, they should be able to work together to determine any state specific issues, if any.
As always, check the information you find on the Internet with primary sources, such as your own attorney.