Commander can be a can full of worms in the wrong playgroup, and the best way to play Magic in the right one. Of all the "mainstream" types of Magic I've tried, it probably has the widest... "fun band"*. That said, when it's good, it's really good
*Caveat: I've seen some competitive constructed players bask in the glory of their deck working one day, and utterly pissed when it didn't the next day, so there's that.
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.