I absolutely love Google Voice, but I don't use it for making calls or sending texts. I use it for the voicemail. You can set it up to be the default voicemail service for your phone, and it blows away anything else. Not only can people leave longer messages, but I have different greeting recordings for different people, I can access my voicemail messages online wherever I am from my phone or from my computer, and it even transcribes the messages in case I'm somewhere that I can't listen to the message, but I can read it. I also have my Google Voice number set to forward to my cell phone, so if there's someone (or something) I need to give a phone number to, but don't want to give them my real one, I can give them my Google Voice number. I can easily block numbers from coming through that call the Google Voice number.
So, in short, yes, sign up for Google Voice. It's a fantastic service that offers a lot of features beyond making calls and sending texts.