IMO, INFN was fully valued, I am not surprised Goldman Sachs downgraded it.  Their reasoning seems correct given that INFN's Metro Network product will have more competition and from bigger and more established players, which will result in lower gross margins.  The company is an excellent company, so even if in the long run it manages to grab a significant percentage of the Metro Market, Goldman is taking the conservative route in recommending clients to lighten up after the massive run the stock has had.

That said, if the company surprises in its next CC, it could just as well go back to the 24 level, in this market I would not bet against stocks with momentum.