Is Simpletax ripping me off, or am I missing something?

For the past 5 years I've used Ufile to file taxes. This year, I have decided to check out Simpletax. Out of curiosity, I entered all my info into Ufile as well to compare the results.

Simpletax says I get a $1400 refund. UFile says I get a $3500 refund. I initially assumed user error, but I've triple checked all my entries and each is identical. What do you think is going on?