If you were looking at prospects (weanlings) and you could only pick one, would you prefer a grandget of DTF x Sun Frost or an FG x Ivory James? The benefit of the FG x Ivory James is a I have a colt by the same sire (sun of Frenchmans Guy) but different dam (daughter of Smoke N Sparks) and really like him...easiest colt to start. But DTF's seem to be super popular as do Ivory James. Same price, really hard to say on the build yet as they are weanlings. 

Really tought call... I would say I have seen a lot of jam up horses of the DTF x Sun Frost cross. I have a Sunfrost grandaughter and would likely look at a DTF for her because of the success there and marketability.

Might come down to the conformation?

From the little bit of info you have provided us, I'd pick the DTF X Sun Frost.    As you can see from my very non-scientific illistration below, the DTF X SF win's 3 out of 4 scenario's.

FG/Ivory James. You get at least 2 Blue Hen mares that way. Plus you are already family with what the stallion produces.