Starcraft, Starcraft 2, Warcraft 3 is for serious people who want to have serious fun with some serious competition, basically is for mature people.
AOE or CC is for people who just want to have some random fun with killing
Total War is for people who just want to have huge realistic battles with awesome fights.
I tried all the RTS games that everyone listed here any my favorite gota be Starcraft 2, the balance, fast pace, skills and all the different scenarios it have to offer is just to great to compete.
Edit: NOTHING CAN BEAT KOREAN E-SPORTS WITH WARCRAFT AND STARCRAFT, SUCKERS, IS THEIR NATIONAL SPORT