Pro- not all muslims are bad or violent people. Con- I cannot readily tell the difference between the peaceful and violent ones.

Pro: I know some people of the Islamc faith.

Cons: islam is not only a religion. It's teachings address all aspects of life, including government. The leaders of Majority Muslim countries are Muslim. The Qu'ran, the Hadith, fatwas all determine Sharia law which guides all Muslims. The biggest con is having Muslims in our Government for the previously mentioned reason. Even though considered a melting pot. Many want to remain separate and change long standing traditions and laws.

I think the biggest issue is the fact many of their societies are simply poor, undereducated and therefore lack rational.
If Christian countries were living in squalor we'd be acting out horrendously and blaming the bible.
That said thought, for me it's the forced marriages that are the most sickening.

One dubious "pro":
It is the most successful social engineering exercise in history, to the detriment of all of humanity.

"con":
Islam is a cruel, oppressive, imperialistic, theocratic, totalitarian political ideology. It is based on the teaching and example of the insane, deceptive seventh century Arabian warlord Muhammad (may his evil words and deeds be forever cursed) who was a plunderer, a mass murderer, a rapist and a pedophile. Islam's only objectives are its own propagation and the establishment of a global caliphate. These are to be accomplished by any means available, including violence, deception (taqiyya), migration (hijra) and rapid reproduction. The well-being of its followers and of humanity in general is not a consideration of the ideology.
The establishment of the caliphate would necessitate the removal or subjugation of existing national, regional and local governments. It should be obvious that this qualifies as treason: There is no good reason why any nation-state should succumb to coercion to accept immigrants who subscribe to a political ideology which advocates treason. It is reasonable and appropriate to restrict or prohibit immigrants who follow the ideology.
Most of us who oppose the Islam ideology are actually sympathetic towards Muslims, who have been betrayed and enslaved by their indoctrinated dogma.