But yes I learned not too long ago that Super Knuckles is pink in some older games, and I had to draw him. In my headcanon, Knuckles doesn't call upon the power of the chaos emeralds often, but when he does you'd better be ready to get out of the way. Like Super Sonic, Knuckles gains the ability to fly while super, and his natural strength is greatly enhanced. There are very few obstacles that stand in his way when in this form.
I like to imagine going super is like a hugeass adrenaline rush. Because of that, it's often safer to come out of super mode yourself instead of running out of rings, or else you run a greater risk of crashing and becoming disoriented. Knuckles is extremely good at managing his usage of rings and will almost always power himself down before he runs out.
As a whole Knuckles basically has a very strong respect for the power that the chaos emeralds hold, and very greatly dislikes anyone who wishes to abuse that power for evil.