My own experience with the Mormons is a good one. They set up hospitality tables for visiting Catholics during World Youth Day in Toronto.
I admired them so much that when I saw what I later learned were two Mormon elders, I approached them to thank them for their hospitality.
They replied by praising Pope John Paul etc.
Then they asked me why I was “still Catholic.” Was I “born a Catholic” and is that the reason? They gave the impression they considered me Catholic because I “didn’t know any better.”
I told them that, in truth, “there is no better.”
With respect to how nice this or that religious group is, this should have no bearing on matters pertaining to religious truth. If I began a church based on total almsgiving, insisting that my members smiled all the time and were warm and helpful to others - that would have nothing to do with WHAT I believed or taught.
I also know unbelievers who do a lot of good works - that is great, but the issue of whether they believe in God and Christ is still a concern.
If we believe that our good works somehow excuses us from seeking God and HIS Church, then we are badly deceived. And I’m not saying Mormons are like that. Objectively, as far as their theology goes - YES, their theology is, against the historic standard of God’s 2,000 year old Catholic Church, wrong.
Catholics should always be hospitable to everyone, including Mormons. If meeting them poses a proximate danger to our faith, then we should leave such alone and not speak with them.
But the goodness of Mormons is also something that has led a number to join/rejoin the Catholic Church, if they have some warm, informative support from sympathetic Catholics.
I have found that, of all the 19th century sects, the Mormon missionaries at the door tend to be the most ill-informed about Mormonism. This is a whole missionary field coming to our very doorstep. Catholics who are prepared by strong scriptural/catechetical study can at least sow the seeds of the Faith in such souls. Mormon souls are tender - handle with prayer!
Alex