masha-russia:

She is not compared to Aerys in the books, not by her allies and those who know her anyway. That is only a show thing. Her enemies though, like the Yunkish Masters and other slavers around Essos, love to spread scary tales about her, such as this:

The more Quentyn heard of Daenerys Targaryen, the more he feared that meeting. The Yunkai’i claimed that she fed her dragons on human flesh and bathed in the blood of virgins to keep her skin smooth and supple. Beans laughed at that but relished the tales of the silver queen’s promiscuity. “One of her captains comes of a line where the men have foot-long members,” he told them, “but even he’s not big enough for her. She rode with the Dothraki and grew accustomed to being fucked by stallions, so now no man can fill her.” And Books, the clever Volantene swordsman who always seemed to have his nose poked in some crumbly scroll, thought the dragon queen both murderous and mad. “Her khal killed her brother to make her queen. Then she killed her khal to make herself khaleesi. She practices blood sacrifice, lies as easily as she breathes, turns against her own on a whim. She’s broken truces, tortured envoys … her father was mad too. It runs in the blood.”

We – the readers – know that it is an absolute lie.

Ser Jorah Mormont and Ser Barristan Selmy compare her to her brother Rhaegar.

Ser Jorah told her this for the first time after she commanded the Dothraki to stop raping the Lhazareen women in Book 1:

“You are your brother’s sister, in truth.”

“Viserys?” She did not understand.

“No,” he answered. “Rhaegar.”

Then when they were in Qarth, and he was trying to “protect” her (book Jorah is not as nice as show Jorah, he has a very predatory behavior towards Daenerys, he mainly was trying to push men away from her so that she had to rely/trust on him only) they had this conversation:

“I am not the frightened girl you met in Pentos. I have counted only fifteen name days, true … but I am as old as the crones in the dosh khaleen and as young as my dragons, Jorah. I have borne a child, burned a khal, and crossed the red waste and the Dothraki sea. Mine is the blood of the dragon.”

“As was your brother’s,” he said stubbornly.

“I am not Viserys.”

“No,” he admitted. “There is more of Rhaegar in you, I think, but even Rhaegar could be slain. Robert proved that on the Trident, with no more than a warhammer. Even dragons can die.”

After Ser Barristan revealed his identity to Daenerys when they reached Meereen, he explained to her that he did not tell her who he was right away because he wanted to observe her and see if she “had the taint” of madness in her (Ser Barristan joined her in Qarth at the end of Book 2, but did not tell her his true name until the end of Book 3). Dany first asked him why did he abandon Viserys in exile, and Barristan answered her:

“Prince Viserys was only a boy, it would have been years before he was fit to rule, and … forgive me, my queen, but you asked for truth … even as a child, your brother Viserys oft seemed to be his father’s son, in ways that Rhaegar never did.“

“His father’s son?” Dany frowned. “What does that mean?”

The old knight did not blink. “Your father is called ‘the Mad King’ in Westeros. Has no one ever told you?”

“Viserys did.” The Mad King. “The Usurper called him that, the Usurper and his dogs.” The Mad King. “It was a lie.”

“Why ask for truth,” Ser Barristan said softly, “if you close your ears to it?” He hesitated, then continued. "I told you before that I used a false name so the Lannisters would not know that I’d joined you. That was less than half of it, Your Grace. The truth is, I wanted to watch you for a time before pledging you my sword. To make certain that you were not …“

”… my father’s daughter?“ If she was not her father’s daughter, who was she?

”… mad,“ he finished. “But I see no taint in you.”

Then in Book 5, in Meereen, Ser Barristan tells her Rhaegar would have been proud of her. After Daenerys flew away on Drogon, Ser Barristan becomes a POV character and he always thinks very positively of Daenerys:

It was his failures that haunted him at night, though. Jaehaerys, Aerys, Robert. Three dead kings. Rhaegar, who would have been a finer king than any of them. Princess Elia and the children. Aegon just a babe, Rhaenys with her kitten. Dead, every one, yet he still lived, who had sworn to protect them. And now Daenerys, his bright shining child queen. She is not dead. I will not believe it.

And there is also an exchange between Tyrion and Illyrio Mopatis, the friend of Varys and the man who arranged the marriage between Daenerys and Khal Drogo in Book 1. Illyrio is one of the main schemers behind the curtains in the novels, he appears rarely but he is playing the game of thrones and trying to put a character on the Throne (I won’t spoil it for you). He knew Viserys and Daenerys for several months, and this is what he tells Tyrion:

“Viserys was Mad Aerys’s son, just so. Daenerys … Daenerys is quite different.”

Nobody who knows Daenerys and who is a reliable judge of character (by that I mean, not the Slavers who wish to restore slavery back) thinks that she is similar to her father in personality. She is nothing like he was.