I bought the entire midnight collection (sans pants) and ended up returning the sweater because the arms are too short and I felt the shoulders were too narrow for me.
I own a ton of reigning champ gear, and I prefer reigning champ sweatshirts because of their unparalleled quality (fabric is a little heartier, seems more robust) and the fit is better suited towards my body type (5'11, 160 lbs, broad shoulders, long torso and arms). I would've had to wear my charcoal villan hoodie with the sleeves always rolled up (I wear medium in everything).
I would say try out both brands if you have the means. You might like one more than the other in terms of fit and fabric feel; at the end of the day it's personal preference.
I've worn reigning champ for 3-4 years and have never had an issue with any of their pieces, after countless washing and wear.
John Elliott t-shirts, however, are of the utmost quality and fit (I own at least 5)! The u-neck and Mercer tees fit me dead on and I would recommend them to anyone, especially those who are tall, broad shouldered, slim.