I used Rosarios 4 Bio Bamboo (100% bamboo) and I must say, I am extremely pleased with the result. It is so soft, and a bit drapey, though I think it turned out lovely! I used 4 mm needles to get anything near the gauge recommended for the pattern.
Bio Bamboo is wonderful stuff, but I think they were out to lunch when they printed the label. The yarn label's gauge is 27 sts and 32 rows = 4 inches with 5 mm needles, but I couldn't even get that gauge with2.75 mm needles (I got 25 sts and 30 rows). And I always knit to gauge. So I wouldn't trust the label, and recommend ALWAYS knitting a gauge swatch with this one.