One finds him lauded often enough by people worthy of respect that it should not matter, and it certainly would not matter to a true Stoic, but I find myself disturbed and baffled by those who denigrate Marcus Aurelius.
I've noted before those Christian apologists, Chesterton and Lewis, who with others seem to have found him to be "unmanly." It has always amused me that that they in particular, and Christian thinkers in general, should assert that "manliness" is somehow significant in philosophy or religion.
Chesterton with his fond recollections of his nanny and his charming reliance on the enlightening effects of fairy tales cannot be said to be manly in any impressive sense; his doubtless glad times in his nursery linger uncomfortably about his writings. Lewis, who at times seems to be deliberately as well as predominantly gullible in his thoughts, is not exactly a paragon of stern fortitude (one might say Roman fortitude) in the face of the facts which he strove to ignore in his "arguments" regarding Christ's divinity. And the Christian ethic as it appears in the gospels is not overwhelmingly "manly" either, I would say, as that word is commonly understood--the Stoic sage and the Stoic ethics seem far more "manly" than Christ and the Christian ethics, even though Christian ethics is based so much on Stoicism. I suspect Chesterton, Lewis, and others had in mind the largely mythic figure of the Christian knight (as described to them by their nannys or Thomas Malory, perhaps) when they thought of manliness and Christianity, but the relation of the knight of history to Christianity is at best tenuous.
But there are also those who criticize the emperor as being "self-consciously good" (e.g.Gore Vidal speaking through Priscus in his wonderful novel Julian). Sometimes his Meditations are criticized as being lacking in style. Sometimes, he is criticized because his Meditations betray uncertainty.
I think his critics forget that what he wrote was not meant for reading by any but himself. He wasn't propounding anything, as philosophers who write for others do. Naturally, therefore, what he wrote is unpolished, and there is no real argument. He wasn't trying to convince or impress anyone. Perhaps more significant in this respect is the fact that he wrote his thoughts in those rare moments when he was not being an emperor--an emperor on campaign in a military camp ("Among the Quadi"). It's likely he was exhausted and worn down by his duties and responsibilities when he took up his pen.
He was not an idle man, indulging in philosophy as one would indulge in luxury. There's no question he was an industrious and hard working ruler. He angered the crowds at the games because he insisted on working during them. His reign was filled with disturbances; wars, rebellion, plague typified his principate, and he spent most of his time as emperor engaged in campaigns against barbarians, which is appropriate enough given the title imperator is a military title, but the fact is that many Roman emperors never had to be military men in any significant sense.
It's not surprising that the Meditations often seem sad. Sadness was to be expected, I think. Nor is it surprising under the circumstances that they sometimes express doubt regarding the existence of Providence. But he clearly states that regardless of whether there is a benign purpose guiding the universe or all is "atoms and chance" as he puts it, it's necessary to continue with one's task and do the best one can. Although I'm not very fond of the word, as I think it's been overused and misused, I can think of nothing more "manly" than such an attitude.
He made mistakes. He may justly be criticized for failing to follow the example of his immediate predecessors in office and adopting a good man to follow him as emperor. Because he didn't, the empire was compelled to endure Commodus. The Christians were persecuted during his rule, and one wonders why he could not bring himself to address that problem in another matter. Although he despised the gladiatorial contests and the games, he tolerated them and sanctioned them through his attendance. He was no Stoic sage.
I suppose he couldn't be, though, and be an emperor of Rome, or even be a good emperor. For the times, he was indeed good. In his Meditations we see what he felt and thought while ruling the Roman world. It can be sad and even grim reading, at times. We see him struggling to be good, and urging himself to be good, in a cruel world. It's not so different now. But I think if any current ruler wrote his/her thoughts at the end of the day, without knowing they would be read by others, and these were somehow disclosed to the world at large, they would seem puny, petty, venal creatures indeed when compared to Marcus Aurelius Antoninus.