Saint Seiya: The Lost Canvas Gaiden provides us short stories of the gold saints, mostly of their stories are from before the Holy War, or from while they were training to be the gold saints, and also some of them are events from after the War. The manga is very nice if you already read the Lost Canvas manga and want to know more about the gold saints – since some of them weren't explored that much in the original manga –, or if you simply liked an specific saint and want to hear some stories about his past. Another thing that might call your attentionin the Gaiden is the friendship of the saints when they were in missions, or while training in Sanctuary, I would never imagine some of them would walk together or even being friends, so it's nice to see their interactions there.
There's also secondary characters introduced in each story, they sometimes are previously related to the saints and sometimes are just characters related somehow with the story that is told. Also the villains introduced in each Gaiden are very cool, and it's also nice to see them fighting with some enemies that aren't related with Hades and the whole story from Lost Canvas, sometimes it's just a normal mission with bandits or something related to mythology.

The art keeps absolutely gorgeous, Shiori Teshirogi never disappoints when it comes to stunning characters and well detailed Cloths. I seriously thought she couldn't improve since the Lost Canvas, but after some years her art keeps getting better and better, I might say that some characters and Clothes look even more beautiful in the Gaiden than in the original.

I would recommend you to read this Gaiden if you already read the Lost Canvas, it's nice if you want to know more about the Saints, and in some stories is nice for you to know about the stuff that happened during the fights, or why the characters are like that, while reading I felt a little bit more close to the characters than while reading Lost Canvas, so that's why I think – as a fan or not of the franchise – this manga is a good reading.