My wife and I have a recurring argument about whether My Morning Jacket is a jam band. The eternal argument, at its core, comes down to this: Neither of us are into jam bands. I love MMJ. She, er, does not.
The bottom line is this: Yes, they are fond of the extended jam - often profusely, and many times in the studio as well as live. This, to me at least, is when they are their, well, not best. And roughly half of any given album tends to plod along at tempos ranging from slow-burning to gooey. And yes, go to their live shows and you can probably be ready for some serious noodling. (No, not this noodling.) But know this: a MMJ live show is positively transcendent, and in that context every single jam is worth it.
But, again in my own opinion, they are at their best, at least on record, when they work against their own jammy tendencies and force themselves to work within actual song structures. And at their best, they are one of the greatest bands in the world. This is sometimes as simple as adding a little melody, sometimes simply picking up the pace, sometimes taking us into dark places.
"Mahgeetah," my favorite MMJ song, actually supports both sides of our argument. Great melody, driving rhythm with some satisfying changeups, and some fret-burning guitar work that rides the line between stunning and self-indulgent perfectly, though it's actually a much better song if you cut it off with exactly one minute to go, when Jim James' Flying V straight into jamland.
Of course, live the outro makes perfect sense, especially stretched out with some Angus Young-worthy guitar burning. This is from the Okonokos live recording, with a slice of vintage weird MMJ humor thrown in at the end: