The change courses vary clearly in countries where the Arab spring revolutions succeeded, in Tunisia, Egypt, Libya and Yemen.
 
It could be said that Libya and Tunisia managed to get rid of their previous regimes and are establishing new regimes to a far extent and despite the internal disputes and disagreements they face,  as natural results of the sufferings they are experiencing due to two autocratic regimes, whose tyranny and corruption had reached the climax.
The two countries need long times to pass the challenges of post downfall of the two regimes.
As the Tunisians are proceeding in an outstanding way up to now in building a new system based on democracy, law, freedoms and rational governance, benefiting from what the former regime has left. But the Libyans are trying to build their state from scratch as Gadafi regime left no real administrative infrastructures, leave alone what they suffer, of what is described as the ( freedom surfeit) that came after a regime that used to represent the worst oppressive, locked regime which used to kill its people due to suspicions and its overthrow used to be an inaccessible dream.
But what deserves to be considered are the Egyptian and Yemeni models on their paths which are similar in some aspects and different at others,  optimistic on some sides and disappointing in others.
Both revolutions overthrew their presidents who ruled the two countries for three decades with the differences in their fates and other distinct differences regarding their cliques.
While the former Egyptian President Mubarak is facing a judicial judgment of life imprisonment, the former Yemeni President Saleh, is enjoying a full judiciary immunity from prosecution, covering all his years of reign.
Also while the National Democratic party of Mubarak is dissolved, the GPC, which Saleh used and is still chairing is a partner in half of the Reconciliation Government "RG".
Also, as Jamal, the son of Mubarak used to be prepared for succeeding his father, is, in prison, Brigadier Ahmed, son of Saleh, who was also prepared for succeeding his father is still commanding the Republican Guard, the strongest brigade in the Yemeni army.
On the other hand there are aspects in which there was a great deal of agreement in the two revolution's paths. The transitional authorities in the two countries were not entirely away from their previous regimes. A military council, which was actually existing, undertook power in Egypt, dissolved the parliament and the Shora councils, elected during Mubarak's era, and gave itself according to a constitutional announcement a legislative power.
It is well known that the army in Egypt didn't use to interfere in the Egyptian politics, however it was known that it is customary authorized to govern Egypt since july1952, in a base which requires that  the Egyptian president should come from among the army on condition that he abandons the military uniform and abides strictly by the civil uniform.
In spite of the freedom atmosphere that prevailed in Egypt since January revolution, and the compliance of the military council to consult the political powers in all the steps it is taking, in the direction of conveying power to the civilians, however the two judgments passed by the Constitutional Court last Thursday regarding the rejection of the political isolation law and dissolving the Parliament elected five months ago, proved beyond doubt that the course of the power transfer procedure has been afflicted by a lot of confusions by the political forces, the cunningness of the military council and the state institution, helping it which is considered to be an extension to Mubarak's regime.
In Yemen, power was transferred from President Saleh to his Deputy Hadi in November, until his election for two years in last February. The election process, witnessed consensus on his personality and clear enthusiasm from the revolutionary youth, however despite all this it could be said that the Yemeni revolution has gone into a course that is more wise and secure in its ends with more achievements to its objectives and visions.
This goes back to a number of reasons, including the long period of the Yemeni revolution , its popular momentum and the split of the Yemeni army, following the dignity Friday massacre on March 18, 2011, which deprived the regime of its legitimacy. The split has also broken the back bone of the army, leading president Saleh to draft a political agreement for his orderly departure. It is an issue that is considered to be on his credit, because the two disputing parties over the revolution know the importance of the agreement which spared the country a destructive war.
 The change of the agreement project through regional and international interference into a GCC initiative, is the issue which the Egyptian revolution lacked due to the fast step down of Mubarak, however president Saleh procrastinated in signature, changing his positive attitude into a negative one. The peaceful revolution momentum continued , accompanied by the huge sacrifices, wounded and arrests among the youth. The regional and international pressure also continued on Saleh to step down until his exposure to the assassination attempt on early June of last year.
Saleh succeeded in obtaining the best conditions for his departure, which is agreed by political revolutionary forces , while they are considered unacceptable concessions by the youth at the change squares. Finally it spared Yemen a civil war. Saleh signed the agreement on November 23, in a deliberate thoughtful way that removed the mines that had been planted by his regime, one by one.
The GCC initiative and its operative mechanisms had provided a clear road map for the transitional period in Yemen, that is not provided by the constitutional declarations in Egypt, which put the carriage before horse. This was proved by the Thursday judgment of dissolving the parliament. The logical attitude stipulates that the military council should go ahead by holding elections for a constituent assembly for drafting a new constitution which determines the shape of the new regime which the elections are held according to it.  
The compatibility among the major Yemeni forces, known as the JMP and their alliance, gave them strength in their negotiation position. This was not available for the Egyptian forces, which didn't succeed in creating an accord between themselves, and to coordinate their attitude despite their close components with their Yemeni counterparts.
Finally one imagines that the spirit of tolerance that distinguished the Yemeni revolutionary forces, by offering immunity to President Saleh, their demand for the transitional justice and reconciliation law, their desire to open a new page free of revenge, helped in accomplishing the fundamental revolution's goals and paved the way before it.
This was not available in the Egyptian revolution which insisted on trying former President Mubarak and issued the political isolation law. These two contrasting images , made a major difference between the two revolutions that requires contemplation.