Full contact karate is proven as the best in K-1 standup fighting. Bas Rutten didn't dabble in karate, he's a fourth degree blackbelt in Kyokushin. They don't just hand those out, you have to earn it through brutal training and bareknuckle fighting. That's why he was so good with those kidney punches in his old fights. They used to allow head punches in Kyokushin kumite, but they stopped it because of serious injuries. They don't use gloves because it changes the way you block, and it's not realistic outside of sports combat. Karate isn't what you see in the movies, or what Bruce Lee says(who NEVER fought any legitimate karate fighter, and had trouble beating a Gung Fu man). It's very practicle. All the kicks in Muay Thai are used plus many more, and a variety of hand strikes, including the jab. It's a complete fighting style, proven time and time to be the best in standup.