It's worth it -- IF you do it yourself. Apple essentially charges you for a new drive and doesn't credit you for the stock drive they don't give you. Its an easy install if you can use a screw driver. You can easily get a 500GB 7200RPM drive for $90 shipped online. Spend a bit more and you can get a WD Black.
7200 drives do not run hotter or use more battery life. Honestly I don't know why Apple still puts 5300 drives in, especially at the high end.