KO
I actually started with KO but switched to HILO about a year in to it. Go figure. Ask ten people and you'll get ten answers.
I'd just say this. There is nothing wrong with playing KO; it is a good sytem, it will get the money, especially if you predominantly play 4D or 6D shoes. I know a guy who gets big money playing KO and he does not TC. Granted his BR is big and his EV in dollars per hour is larger than probably yours, but the point is KO works.
The biggest advantage to HILO that I see is that almost every generalized analogy, simm, or reference made about how to play this game is made using HILO as the count. If you use another count, like KO, and are just learning, you have to go one other step and adapt the lesson being taught to your specific system.
None the less, there are several posts on another site re-visiting the idea that the system itself (KO, Hilo, etc) is way down the list of considerations in figuring out how to beat this game.
Learn BS then learn a system. Then discipline yourself to only play the games with good rules and good penetration while being financially prepared to bet small when it's bad and spread big when you have the advantage.
KO is fine -finding the good rules and pen, while spreading big when you should, is what wins the money.
Good luck.