In ExChange they already broke up and it's kept a secret who they dated. In Change Days the contestants know who the Couples are from the start and are still dating. But otherwise the concept of those two dating shows is the same: They live together under one roof for a while and go on dates with other people and decide in the end if they want to continue their old relationship or move on to someone new.

Couples live together with other couples and go on dates with other people and have to decide in the end if the want to continue the old relationship, start a new one with someone they met here or leave single.

Both are about a team of criminals working together for a bigger goal.
Bad guys is a bit darker so the focus is a bit more on the psychological & crime elements.

In general it is similar because it is about con artists

Specific similarity is that main leads have the intend of stealing money from those who obtained that money illegally in the first place.