For comparison we have:
OPI My Chihuahua Bites vs. Essie Too Too Hot vs. OPI Cajun Shrimp
Not 100% dupes but they are all really close.
I examined these under my bathroom lights and came to the following conclusions:
The closest to being dupes are the two OPIs.
OPI My Chihuahua Bites is more pink toned than OPI Cajun Shrimp.
The darkest of the trio is Essie Too Too Hot.
OPI Cajun Shrimp & OPI My Chihuahua Bites are more orange than Essie Too Too Hot.
Essie Too Too Hot has the strongest red undertones of the bunch.
OPI Cajun Shrimp & My Chihuahua Bites have the same formula.
Essie Too Too Hot is more 'squishy' feel to the formula (which may be my favorite).
Do I need all three? Absolutely not. If I were going to swap one it would be one of the OPIs, most likely My Chihuahua Bites as much as I love the name. If the world was coming to an end and I could only keep one it would be Essie Too Too Hot.