I guess I just don't see number portability as a huge issue. I have changed providers 3 times in my life. I am on Nextel now and when I changed two years ago from Centurytel to Nextel, I had to pass my new phone number on to everyone I know. Today, I know more people but it isn't too hard to just let everyone know of the change. I will say it is a nice convenience though.
Will I change? No. I like Nextel and have no plans to move to another provider. IMHO, anyone who sticks with a crappy provider all because of a phone number is a moron. You are paying for the service, might as well pay for good service.