Due South Noticeboard

My apologies to the mods if this post is inappropriate...

I am planning to (finally!) buy Due South on DVD, and noticed that there are competing releases, one from Alliance (Canada) and a cheaper one from Platinum (USA). According to an Amazon reviewer the more expensive Alliance discs have superior picture quality. Is this true? Also, does either set come with extras (commentaries, making-ofs, etc.), or are both just the episodes?