Not sure about riding one dude,I don't think the originals were the strongest,i could be wrong. thought i heard about a copy one on here(or maybe it was real)that broke and just spun on it's shaft.They do look pukka as Bendy said with a decal and i did own one a while ago but never rode on it.Value wise hard to say.Some copy bits make good money and I would imagine these are quite desirable as the real ones are expensive.I suppose about £40-50 would have to be the limit as for any more you are in the realms of buying a better quality branded stem.Others may have differing opinions