"Although this would seem to be a field ripe for al-Nahda recruitment, many Tunisians are cautious about the Islamist party. The youth who led the revolution have never known anything but single-party dictatorship under Ben Ali, and were not exposed to the ideas of al-Nahda. The Tunisian middle class is wary of al-Nahda, which has been accused of extremism and terrorism, in particular following the incidents in the early 1990s, when al-Nahda activists attacked an RCD office in a Tunis neighborhood, killing one civilian, and threw acid in the faces of certain individuals. The shock of these incidents still resonates today, and Ghannouchi has recently admitted that party members committed mistakes in the past, though he stressed that those were individual acts not authorized by the party leadership...
"Although al-Nahda has succeeded in establishing itself within the coalition pushing to consolidate the revolution, it is still challenged by internal rifts and competition from other Islamists. Disputes surfaced as the younger generation of al-Nahda members forced founding member Abd al-Fattah Morou from the leadership body in light of demands that al-Nahda be more self-critical regarding the violence it committed in the 1991 Bab Souieka incident. Morou is now openly criticizing al-Nahda and planning to form an independent party. In addition, the official composition of al-Nahda’s executive bureau has seen significant changes, including Rachid Ghannouchi’s announcement from London that he was stepping aside from active leadership in favor of spokesman Hamadi Jebali.
"Fragmentation is a real threat for al-Nahda; some 50 political parties have been legalized, some of which are openly Islamist in orientation and thus are potential competitors for al-Nahda’s traditional constituency. Al-Nahda is also faced with unexpected emergence of a Salafi youth movement, particularly Hizb al-Tahrir, which was denied legal status by the government after it openly proclaimed its primary objective to be forming an Islamic Caliphate and abolishing political parties. This growth of fundamentalist Salafism puts al-Nahda in an awkward position, and may force it to reposition itself after the Salafists have led demonstrations chanting bigoted and anti-Semitic slogans, and attacked liquor stores and unveiled women."
There are two things about this which I think are generalizable to most of the Arab world. One is the possibly for major Islamist opposition groups to fragment in a new multi-party scene in which the different strains of thought may become more evident. The other is the rise of the underground salafi trend while these movements have, in different countries, been organizationally repressed, co-opted, or both.