Different burner brands seem to burn better with different brands of dvd's. Personally I use Verbatim.

One reason it's not as crisp & clear is Toast will re-convert the video from whatever format it was to MPeg-2 dvd format. Each conversion stage will mean throwing away some information & 'some' loss of quality. Also as suggested, if the video file was ntsc & you converted to Pal or vice versa, then yes, there will definitely be some colour, brightness & other issues. Another reason is that viewing on Computer Monitor screen smaller than TV, the pixels can only stretch so far. When the video was converted down to the format you downloaded it at, it's pixel dimensions will have been reduced. eg: Pal format of 720 x 576 pixels, whereas the video you downloaded was probably downsized to perhaps 352 x 240 p.

If it is possible to connect your computer to TV, play the file you downloaded thru the TV & see if there's much difference compared to the DVD.

Another reason for the quality difference might have been your burning quality settings within Toast.