I wholeheartedly agree with you about the "when it's good, it's really good" statement. The biggest issue I have with EDH is that when it's bad, it's miserable.
For example, I had a game at my LGS where someone soft locked everyone out of the game using Yosei, the Morning Star and a couple of repeatable clone spells. The rest of us kept drawing removal and trying to use it with the minimal amounts of mana we had, but after about an hour we realized we couldn't win.
That's obviously just a single example, but many more exist (looking at you, every Nekusar, the Mindrazer player ever). GRBS is rampant in EDH, and many of the worst offending players usually have about a million ways to protect their BS from interaction.
I seem to be in the minority, but EDH going downhill and turning into GRBS started when wizards started trying to put out cards for it.