The GT-R is an amazing car for performance. The overall test reviews that I have read have not been as favorable recently.
And, you are talking somewhere in the neighborhood of $40,000 more for the GT-R vs the Hellcat. So, you could have a Hellcat and 1500 truck (or mid-sized SUV) to drive when the weather is less than the ideal, or you can have a GT-R.
Don't get me wrong, the Nissan is impressive. I would like to drive one myself. But, I'm not sure how many people are likely to cross shop them.
GT-R vs Viper is probably more realistic.