PHP is the most popular language in the world for websites. What this means to you is that you'll always be able find a developer that works in this language and rates will be less than in more obscure languages. I've seen sites that are still coded in Cold Fusion - good luck finding a lot of those developers.
Another bonus of PHP's popularity is that of stability. Some of the most popular websites on the internet use it which proves that the language can scale to meet your growing needs.
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Let's talk. I have a lot of experience working with both large and small companies. We can brainstorm your idea and see if we are a match. You should never rush your decision when finding a developer. You need someone that will become a part of your company and treat it with the respect that it deserves.