In my experience evaluating any training programme (reactions, learning and resulting behaviour/performance - forget the ROI bit as it's usually not possible) is not a quick or cost-effective procedure.

I've always wondered what the fuss is all about. If a training programme has been shown necessary by undertaking a proper needs analysis and has been designed and delivered in the most cost-effective manner, why on earth you would need to evaluate it, irrespective of the model chosen?