The large majority of people go Aldor; few go Scryer. THis is both good and bad. Scryer rep items cost more due to fewer being up, though at the same time you can make a killing trading Aldor rep items for them. Also, due to the lower population on SCryer, Scryer-specific patterns/recipes aren't around much(Runed Blood Garnet for example) and can give you an economic edge/monopoly ;p

In the end though, check wowwiki.com's comparison listing of the faction rewards and see which rep rewards'll benefit you more :p