Hate to rain on the parade here, but this is one of the few restaurants at WDW that I will actually say was just AWFUL when I went there.
Stopped in for lunch on a weekday with no ADR because the menu looked good. Restaurant was not at all crowded, so I was somewhat surprised to see a TON of people waiting in the lobby, and be told by the hostess that the wait was 20-30 minutes. Still, we figured it's Disney, so what the heck. While waiting, I noticed that the entire staff seemed to be extremely disorganized - they would call a group to be seated, and then take them to to a table, only to find that the table was still dirty (keeping in mind that, as I said, the restaurant was only about half full, so there were plenty of open tables), and then make that group wait another 10-15 minutes for someone to get up from another table. The hostesses were literally running around like chickens with their heads cut off.
Once we were finally seated (45 minutes later), things unfortunately got worse. While the server was friendly enough, the food left a LOT to be desired. I ordered the Penne Bolognese, and was extremely disappointed. The sauce was not at all flavorful. My general rule is that if I have to pour a ton of salt on pasta sauce to make it taste like something, we have a problem. There was also VERY little meat in the sauce. I'm sorry, but a bolognese sauce (by definition) is supposed to be a relatively thick, meaty sauce. This, however, was more like a bland, flavorless marinara sauce that it seemed like they had accidentally let a few chunks of meat find their way into. Oh, and did I mention that when it was served it was only lukewarm? Yeah, I was thrilled.
The person I was with had soup and salad, and that wasn't great either. The salad dressing, which I tasted, was nearly as bland as my pasta sauce, though I will say that the greens were fresh and crisp. The soup was again lackluster, and following the trend, served at about room temperature (seriously, were the stoves broke or something that day?).
All in all, I found Portobello to be an utter disappointment, and will never go back. There are many better options in DTD for either lunch or dinner. Or, if you're dead-set on Italian, give Il Mulino a try - by far the best Italian restaurant on property, albeit a tad pricey.