Been to tignes, three valleys several times, can't go wrong.Val Thorens is higher than Meribel and Courchevel(s) butr is often more crowded, Meribel is a good location to stay as you are between val and courchevel. In my opinion Courcheval is the best for carving out of the three as it has better grooming, ie more chord not mash potato ****. The pistes are wide too. This opinion was seconded by a racer who works in a rental shop on the main street in val thorens, he rides a volant excel 175cm so keep a look out for him. Hope this helps.
I am at bath uni so get good deals with them, usually to 3 valleys so would not know about package deals.