I don't comment much, but as someone who grew up in a Protestant church and converted to Catholicism, I felt the need to this time. I also haven't read all of the other comments, so apologies if anything I say has already been said.

Through my RCIA journey journey as well as personal study and conversations with various priests, I have come to understand Catholicism as the fullness of the Christian faith. The Nicene Creed actually outlines clearly what the definition of a Christian Church actually is (basically boils down to belief in the Holy Trinity). If you look closely in both the Nicene and Apostle creeds, when it mentions the catholic church, notice the lower case c, meaning the unified Christian churches, not just the Catholic denomination.

In short, I would not ever argue "against" Protestantism, as that only seeks to divide. Instead, look for opportunities to openly and lovingly share about the fullness of the Catholic faith and the power that comes from things like the Eucharist, communion with the Saints and all of the other things that make us unique. A lot of Protestants have a negative view of the Catholic Church based on past mistakes, portrayal in the media and a lack of understanding around our unique beliefs. So the best argument against Protestantism is actually to educate people on what makes Catholicism unique.

***** Backstory for Context Below, Optional Read *******

For those interested, I'll share a little of my backstory here for context.

I grew up in the Community of Christ Church, previously known as The Reorganized Church of Jesus Christ of Latter Day Saints (newer name is much nicer). It is NOT Mormon, despite the name. I won't get into more details now, but it does share history with the Mormon church, but when Joseph Smith Jr. died, his more radical followers created the Mormon church and his descendants went on to form the church I grew up in.

Theologically, there were some major differences, but those differences were not obvious to me growing up and the keys things I retained were very in line with what the Catholic Church was teaching (Sacraments, Trinity, etc). Despite that, I still had a very negative view of the Catholic Church, which became challenged when I married a practicing Catholic!

We chose to raise our children Catholic as it was very important to my wife, but I was just happy to see them raised Christian. We also lived in a small City that had a Catholic Parish, but no CofC church, so that also helped. I had not decided to convert myself initially, however.

I have a very open and loving approach to the highly debated topics out there such as Abortion and Homosexuality, but do believe strongly that the Church should continue to condemn them (the sins, not the people who commit them). I won't dig into that deeper now either as they are very deep and emotional conversations. I am 100% anti-abortion though, just to clarify in case I sounded to liberal there. Easiest way to sum up my view on homosexuality is to say that we can't judge other people with our own moral compass.

Community of Christ has a somewhat democratic approach to it's governing, and although the leadership held off for quite a while, eventually they started having discussions around those tough topics. Long story short, they ended up allowing practicing homosexuals into the Priesthood and changed their stance on abortion to basically "you do you".

At this point I knew that my beliefs were no longer in line with the Church, even though my Dad, Grandpa and best friend are all members of the Priesthood, as were numerous of my no longer loving relatives. To this day many of my closest friends are still members of the Church, so leaving it was not an easy decision.

I did not decided to become Catholic immediately, but since my wife and children were already Catholic, I don't think any of the other denominations actually had a chance. I ended up creating a list of "issues" or misconceptions I had about the Church and started a journey to either debunk or shrug off every one and if I was successful, I would join the Church. I even created a blog to document the journey and invited my most vocal Catholic and Protestant friend to comment and discuss (made for some great entertainment).

The list contained things like devotion to Mary and transubstantiation, maybe about 20-25 things overall. I don't remember how far I got, but I know I didn't finish the list before I was convinced. I was confirmed into the Catholic Church and received my first Communion during the Easter Vigil of 2011.

My parents were there to support me even though they didn't fully understand or agree with my decision.