I mostly use Offray too. The 1/4th inch ones. Mostly because it's the right size and look (shiny on both sides, lol) and there are so many colors. My only issue is sometimes it's kinda stiff. I looove adding ribbons to my ponies. I feel like it just completes them. I have like a zillion different colors (don't usually care to match the original colors they came with).
Also, the 1/8th inch ribbon is a decent size for G4s (and other tiny ponies) if you don't want them to look like they're wearing big huge bows.