I've been renewing mine online for years, but I don't think it makes any difference whether buy it online or in person. I'd still buy them online to speed things up at bit when you get to the park; fortunately, KD does a pretty good job at processing passes quickly.
Be sure to check out the food booths at the Spring Bloom Festival. Not exactly Epcot or Busch Gardens, but they had some good offerings last year.