If you are asking if you can use .mp4 for DVD, then no, DVD must be MPEG-2 always, it is an exact specification. For other purposes like the web or portable devices, then .mp4 (H.264) is the better choice. It is a more efficient codec, meaning at low bit rates it looks better than MPEG-2.
About quality, if you start with an HD source, DVD will never look as good because it is SD (standard definition). To match the source quality would require Blu-ray disc which is HD.
Not familiar with export options from EDIUS, but from Premiere, use File > Export > Media and choose "MPEG-2 DVD" for the format and then choose a Preset such as "PAL High Quality". Then you will need to adjust the bit rate to accommodate the length of your program. Just do a web search for "bit rate calculator" and there are many to help you find the correct number to enter. For longer programs, use VBR encoding, and when starting with an HD source, check the box for "Maximum Render Quality" as this helps with the downscaling quality.
Is your source widescreen 16:9 format? If so, you might need to export as 1024x576 using square pixels (1.0 pixel aspect ratio) depending on the viewing hardware/software. If working with 16:9 and the playback looks like 4:3, then try changing the size.