The problem with "Christian Mingle" is it seems unsure whether to be a Christian movie or a comedy-romance, and it ends up being not particularly good as either.
I can understand it not wanting to get too full-on Christian and preachy, but the result is that the Christian message is so diluted that the Christians coming off looking pretty bad. So if they were trying to make a good advertisement for Christians, they failed.
When not-so-Christian Gwyneth meets the church friends of her new boyfriend Paul, they immediately assume she know dozens of Bible verses off by heart, and begin smelling a rat when she doesn't. Not only it is cringey, but it's unrealistic.
But the trouble is there is just enough explicitly Christian content for this to work as a romance either, because it's also (clumsily) about Gwyneth's journey to faith.
Finally, the Mexican village scenes. Other reviewers have commented about how inauthentic they were. I don't know enough about Mexico to comment, but I will say it was hard to take it seriously when it looked so much like the village from The Three Amigos!