It does have a good reputation. I don't understand why you would think otherwise.
Just because 2700+ rated GMs don't play it as often as another opening, doesn't mean it's bad. Most of them probably grew up playing the opening against their friends over and over and over again.
People at the top level tend to prefer the Ruy Lopez, I think, because there are a whole variety of different plans involved and there's a huge mass of opening theory to it, making it slightly more difficult, I would imagine, to prepare against the Spanish Opening than the Italian one.
However, that's not to say that you can't play very good games with the Italian Game. You can. People do.
I use a database of master games (2000-2012 years, 110.000 games aprox. all players +2400 FIDE).
After 1.e4 e5 2.Nf3 Nc6 3.Bc4
white obtain 54,3% of total points and the draws are 52%.
After 1.e4 e5 2. Nf3 Nc6 3.Bb5
white obtain 54,9% of total points and the draws are 52%
the results are very similar, I don't understand why the Italian Game hasn't a good reputation.