To compare scientology christianity and islam to the five points from the definition of cult from the cult information centre.

Definition of a cult from the cult information centre

1) Uses psychological coercion to recruit indoctrinate and retain members

christianity : yes
scientology : yes
islam : yes

2) Forms an elitist society to which all members are to aspire

christianity : no, it does have a personality to aspire to though (jesus
scientology : yes, the entire goal is to become 'clear' like the elite few and to spend tens of thousands of pounds to the church doing so
islam : no, same principle as christianity just different personality (mohammed)

3) Founder/leader is self-appointed, dogmatic messianic, charismatic and unaccountable

christianity : yes and no, jesus was self-appointed son of god (no objective verification) but he wasnt unaccountable to the same degree as Lron and mohammed are.

scientology : yes, Lron was entirely self appointed, dogmatic to the extreme,unaccountable to anyone. anyone saying bad things about the CoS will have their credibility attacked regardless of whether what they say is true or not.

islam : yes mohammed is self appointed, any criticism of mohammed is regarded as an attack on islam, rendering him totally unaccountable.

4) Beleives end justifies the means in raising funds and recruitment and retainment of members.

Christianity : no christianity doesnt try and raise funds and recruit people at all costs (barring some extremists)

scientology : yes, in scientology there sole objective is to cleanse the world of thetans at all costs, they have hundreds of corperate fronts, and charge their members huge sums of money to remain, attempts to leave are met with threats of "disconnect" from current church members, and legal threats if they reveal passages of church sripture to outsiders. It also runs charity programs with incentives to join the organisations.

islam, unknown, i lack any knowledge on this part of islam

5) It is harmful to most of its members and society in general.

to avoid baiting the thread off topic ill only consider scientology in this one, it is most definately harmful to its members, taking large percentages of their incomes, engaging in underhanded recruitment campaigns and promoting alienation of outsiders, it is known for intimidation and slander tactics against news organisations, individuals and companys who do not treat it favourably, Was convicted as an organisation of the largest tax fraud case in human history, and harms the legitimate practice of many psychiatrists through lies and industrial espionage.

so while christianity and islam indeed have their bad points, scientology is far more damaging for society than the other two.