Here are two additional flattering portraits of Cao Cao (translated by Dr. Achilles Fang).
Sima Guang, in Chapter 69 of the ZZTJ, wrote:The [late] King knew men well, and was a good judge of them. It was difficult to dazzle him by false display. He recognized men of talent and promoted them, irrespective of humble origin; employing them according to their abilities, in each case he made the best use of them.
In the face of enemy ranks he remained calm and unperturbed, as if he had not thought of battle; but seizing his opportunity, he would strike for victory in exuberant spirits.
In acknowledging and rewarding service he was not one to begrudge a thousand gold pieces, but to those without merit who sought to profit from his largesse he would not give a single cash. In enforcement of laws he was strict and unrelenting, always putting transgressors to death; sometimes he shed tears as he looked at them, but he would neve grant a pardon. By nature he was temperate and frugal, not given to pomp and adornment.
For all these reasons he was able to bring low the numerous powerful men of his time, and to conquer well-nigh the whole empire.
The author of the Wei shu wrote:[Cao Cao], since he governed the whole empire, mowed down the numerous scoundrels. In his military operations, he followed in the main the tactics laid down in the Sun-zi and Wu-zi. In accordance with different situations, he took strategems; by deceiving the enemy, he won victory; he varied his tactics in demonic fashion. He himself wrote a book on war, consisting of a hundred thousand and several tens of thousands of characters, and when his generals undertook any campaign they all followed this new book. Furthermore, on each occasionhe gave them personal directions; those who obeyed them won victory, and those who did not were defeated. In the face of the enemy on the battlefield, he remained unperturbed, as if he had no intention whatever of fighting; but seizing his opportunity, he would strike for victory in the highest spirits. This is why he always won victory whenever he fought, not a single instance of his successes being attributed to mere good luck. He knew men well and was adept in judging hem; it was difficult to dazzle him by false display. He picked Yu Jin and Yue Jin out from the rank and file, and Zhang Liao and Xu Huang from among the surrendered forces; all of them became his supporters and achieved merit, becoming famous generals. Furthermore, the number of those whom he picked up from mean and insignificant positions, and who eventually rose to be governors of provinces and prefects, cannot be counted. It was thus that he laid the foundations of his great work. He cultivated both the art of peace and the art of war: during the thirty-odd years when he commanded troops, books never left his hand. During the day he attended to military matters, during the night he applied his mind to the Classics and their commentaries. When he climed a height, he would always compose verses. When he made new poems, he would set them to pipe and string, and they all turned out to be excellent songs. His talents and strengths were unsurpassed; with his own hands he could shoot down flying birds and capture ferocious beasts alive. Once he shot down sixty-three pheasants in a single day at Nanpi. When palaces were constructed and machines repaired, he always laid down rules which proved to work to the utmost satisfaction. By nature he was temperate and frugal, not given to pomp and adornment. Ladies of his harem did not wear any embroidered garments, his attendants did not have two pairs of footgear. When his colored curtains and wind-screens were damaged, he had them patched; he had his bedding only for keeping warm, devoid of borden ornament. All things of beauty and elegance which he obtained as booty from captured cities and towns, he would distribute among those who had shown merit. In acknowledging and rewarding service, he was not one to consider a thousand gold pieces too much; but to those without merit who sought to profit from his largesse, he would not give a single cash. Gifts presented to him from the four quarters, he shared with his subordinates. He was of the opinion that the funeral service of the time was too extravagant and useless, the vulgar carrying it to excess; he therefore made a stipulation as to his own funeral, that no more than four basketfuls of clothing were to be buried with him.
And here is one (also translated by Dr. Fang) which is a mix of both "good" and "bad."
The author of the Cao Man zhuan wrote:...But in the maintenance of the laws he was hash and exacting. If any of his subordinate generals had better counsels of war than his, he would find an opportunity to put him to death under the pretext of some law; and none of his former associates and friends who had earned his grudge were spared alive. When he put a man to death, he used to look at him, weeping and lamenting over him, but he would never grant a pardon...."