There's no appreciable benefit to getting summer crops like tomatoes and peppers into the ground at the end of April compared to the beginning of May. Sure...if there's an extended warm spell you can take advantage of, then there can be benefit, but for me the potential benefits (small percentage chance) don't outweigh the benefits of leaving the planting until a couple weeks later.
Unless the extended forecast shows warmth, I almost always plant in the first weekend of May. There are times when the roots are bursting at the seams and the plants just need to be given room in the ground, but even then it's got to be a calculated decision.