Split Testing Options

[ProMedia]

I'm wondering if anyone has any opinion on this split testing question. I'm using LeadPages for landers on my campaign. I'll be using maybe Propeller ads or Microsoft ads for advertising. Is it better to use the split testing features of LeadPages, or.... use run the split test on the ad platform by simply creating ad variations? From looking at Luke's discussion around ad management and analytics, and I'm leaning toward doing the split testing on the ad platform and NOT on LeadPages. I think there might be more data from the ad platform. Right? wrong? or out to lunch?