People mocking SC underestimate the power of the Speeder Trikes. With a good range (outranging every T3 MBT) and as the fastest unit in the game (outrunning every artillery except Magnetron and Basswave; yes, I think I have seen it outrun those Hailstorm projectiles), those are one of the best anti-tank weapons around, second to the Zephyr (with their rate of fire, perhaps they have a better damage output than Zephyrs D:). Not to mention they fire on the move. Their only weakness is their HP, so like every other SC unit, a commander should avoid letting them take damage.
In BR2 they will be immune to EMP, and really, nothing in Chinese T1/T2 arsenal can beat a team of them commanded by a competent commander (in BR1 the only counters was the EMP mine, Yunru, Dragonflies, Centurion, and T3 base defences; the rest can be kited - the EMP immunity eliminates the first three).
How about Desolators (they hit immediately)? Tyrants and Plague Splatters are great against infantry and good against structures. You don't send Tyrants against Nuwas. That's what the Speeders are for.
I think I have won more games as SC against China than the other way around. Taking out Qilins and Terror Drones the moment they come out from the war factories WITHOUT GETTING HURT... is satisfying.
SC against the US, that's another story.
Speeders in MO are similar to the rocket buggies in Generals.