It takes ages to get good at

It took me about one week to reach a basic competency, two weeks before I was equal in both (though this was partly because my QWERTY speed had also fallen), one month before I reached my pre-Dvorak average speed, and I capped out at about 30% faster in Dvorak than I was in QWERTY.

(Note: my methodology in testing this was very imperfect. It relied on typing the same passage on each keyboard layout, once per day, changing the passage each week to avoid too much muscle memory. Certainly not scientific, but relatively useful as a demonstrative.)

In a broader sense, my average comfortable typing speed in QWERTY was about 60–70. When speed-typing, I could push that up to 80. And the top speed I would hit in typing games was about 100–105. In Dvorak, those numbers shifted to 80, 100, and 120.

Granted, the comment above (or it might have been one of the very few good points in the article linked from that comment, I forget) made mention of the fact that some of the benefit is not in the keyboard layout itself but in the act of re-learning as an adult. I strongly agree with this. A secondary part that is loosely related to this in practice (though not at all in theory) is that by learning Dvorak you are not just "re-learning as an adult", but you are forced to learn proper typing technique. Hunt and peck obviously doesn't work when looking at your fingers shows you the wrong letters because the keyboard hardware is labelled according to QWERTY. Even a sort of situation where you are mostly touch typing, but imperfectly with the need to glance down occasionally, even if just for reassurance (which is where I was at with QWERTY) does not work with Dvorak. You become—you must become—a fluent typist. This may not be theoretically an advantage inherent to Dvorak, but for so long as the rest of the world is using QWERTY, it certainly is, as a matter of fact, an advantage. And for that reason, even if no other, I do strongly recommend anyone even vaguely considering it to switch.

causes a lot of little annoyances when random programs decide to ignore your layout settings

Not a problem I've encountered very often.

or you sit down at someone else’s computer and start touch typing in the wrong layout from muscle memory

This does happen. But personally I have found that my QWERTY speed is still faster than most people's, even if it's now a lot slower than either my Dvorak speed or what my QWERTY speed used to be. It takes maybe 10 seconds to adjust mentally. And if it's a computer you're going to be using regularly, just add Dvorak to it—it's a simple keyboard shortcut to switch back and forth.

or games tell you to press “E” when they mean “.”

Games are one of the most frustrating, in part because of the inconsistency. The three different ways that different games handle it. My favourite are the ones that just translate back into QWERTY for you. That listen for the physical key press, then display on screen an instruction that assumes QWERTY. My second favourite tends to be in older games only, and it's where it listens for the character you typed; on these it's as easy as just quickly switching back to QWERTY while playing that game. The worst, but still very manageable are where they listen for the physical key press and display the correct letter for that key according to Dvorak. But you quickly learn to associate a key with muscle memory, so it's not really an issue in practice.

Anyway, all of this is wildly off topic. Because my original comment was memeing. Nobody was meant to take it seriously. It was, as the kids say, for the lulz.