I download the SVCD (PAL) sample from this site and burn it using Nero.

On my Scan 2500 standalone DVD player, it displays in some places yellow & pink lines (macroblocks?) just for a few seconds and the sound can hesitate for a second as well.

Can the media (cheap) and the burner (speed) effect the picture/sound performance or is it just my DVD player?

The player plays VCD no probs, and is able to accept SVCD's.