If you want to export to DVD, then by all means use a good MPEG-2 encoder. There's lots of excellent options, my personal favorite is the free HC encoder. It's fantastic!
If you are wanting to make AVCHD DVDs (aka HD video on a DVD5 or DVD9), then you should probably either leave them as-is per neuron2's suggestion, or possibly re-encode using x264 if anything.
I couldn't suggest any other H.264 encoder, as they've all been unimpressive to me
~MiSfit