Obviously EX King has great normal pokes just like Reg.King both rendering them excellent zoners.
Ex King however, has to rely more on her pokes more for anti-air strategies whereas Reg.King has

+P Surprise Rose and more importantly beefed-up

+K Tornado Kick as anti-air options. It is curious that they gave Reg.King

+P AND

+K as anti-air options whereas Ex King gets none (she has to rely on, albeit an abusive one, Surprise DM). On a side note, I always thought it'd make more sense if Ex King got the

+p seeing she has the DM counterpart...peesh.
Ex King's full screen projectiles do help to a certain degree, but it's not like she has the unblockable bug, and it's only Reg.King's B version Venom Strike that doesn't go full screen (it should be noted, that Reg.King's D version Venom strike technically isn't full screen--one pixel away, just like Mary's D version Straight Slicer).
Furthermore, King is arguably most effective half screen's distance anyway (which applies for 90% of the roster anyways).
I'll definitely admit that EX King's Double Strike DM is amazingly easy to combo, damaging and effective.
On the other hand, Reg.King can Q.Max into her Illusion Dance (qcf~hcb+k)DM. Silent Flash DM is prolly the least effective of the four DMs.
All DMs considered, I'll give it to Ex King due to abusable Surprise Rose and Double Strike's aforemention versatility.
Ex King's PS2 Challenge Mode combo however just takes the cake. The damage for a non-DM combo is disgusting (although Reg.King's non-DM corner combo does close to 50%--nothing to scoff at either).
In sum:
Tornado Kick and anti air options in general- Reg.King
Projectiles - Ex King
Combo ability and overall damage ability - Ex King
Better DMs - Ex King
Winner - Ex King but Reg.King isn't to be taken lightly either