Certainly it is hard to find two  Biblical characters that are more different than משה רבינו and  פרעה. No one has ever reached or will ever reach a higher spiritual level than that of משה. The תורה testifies ולא קם נביא עוד בישראל כמשה אשר ידעו השם פנים אל פנים. On the other hand,  פרעה, in an exceptional moment of recognition of the  truth, expressed a  "הודאת בעל דין"   when he acknowledged "השם הצדיק ואני ועמי הרשעים."

Nevertheless, there is an additional more subtle, but nevertheless significant distinction between the two that should be noted, a distinction which is to some extent at the root of the blatant aforementioned difference. 

In his book קובץ מאמרים, Rav Elchanan Wasserman הי"ד addresses the following question. How can we understand that which הלכה obligates every Jew, even at the relatively young age of  בר מצווה, to believe in the principles of our faith, such as belief in G-d and תורה מסיני.   After all, there have been great philosophers that have not been able to come to believe in G-d as we "know" Him. ( Rav Yehuda Halevi in the כוזרי takes the approach that the basis of our belief is our very reliable מסורה which the philosophers did not have.) Rav Elchanan responds that the tenets of our faith are somewhat simple to arrive at, provided one truly seeks the truth in an unbiased manner. After all, the תורהtells us that השוחד יעור פיקחים ויסלף דברי צדיקים. Even the wise can be swayed by any form of bribery. Thus, suggests Rav Elchanan that with all the intellectual ability ability the philosophers had, they did not reach the אמת due to their "שוחד" of their desire to live their lives without the restrictions that belief in G-d might place on them. (One expression of this phenomenon is found in the writings of Aldous Huxley who confessed at some point, "I had motives for not wanting the world to have meaning ; consequently assumed it had none.") Thus a lack in  מידות טובות can generate a prejudice which leads to a lack of אמונה.

The subtle difference between משה רבינו and פרעה  is with regard to their מידות. We are told that פרעה  was a מלך חדש אשר לא ידע את יוסף. He didn't have הכרת הטוב to יוסף.  Our Rabbis teach us that this led to his then denying G-d. As an individual who only had his personal interests in mind, there was no reason for him to think about what is the proper way to deal with the Jewish people or with the message משה רבינו was conveying in the name of G-d.  On the other hand we find that משה רבינו towards the beginning of the Parsha demonstrates a sense of justice and truth even when it meant endangering his life. Those traits set him on the path to be able to soar to the height of the angels.

It is interesting to note יתרו, in contrast to פרעה  did have the sensitivity of a מכיר טובה. After all, when he is told by his daughters that they were saved by this Egyptian man, his reaction is למה זה עזבתן את האיש, קראן לו ויאכל לחם. It has been suggested that this sensitivity and expression of שלמות המידות led him towards being a seeker of the truth and eventually a גר צדק.

 May we all be זוכה  to a purity of heart that will  bring about G-d's answering our request וטהר ליבנו לעבדך באמת.