I've read up on this, and the drawback on silicon hoses is that they're not vapor-tight. The problem is that unlike rubber, silicon allows water vapor to pass through it. And given that it's very hot water vapor in the cooling system of a car or truck, the level of coolant will progressively and invariably go down. Silicon coolant lines are fine for race vehicles that receive an overabundance of meticulous professional maintenance, but are trouble on a vehicle that is driven regularly and maintained in the normal fashion.
Bottom line: If you install silicon coolant lines on your vehicle, you'd better be a maintenance freak willing to be under the hood a lot and willing to buy a lot of coolant.