Choosing a resort depends on what you want to get out of the season. What are your priorities?
Live to ride powder?
Spend hours working on your tricks in the park?
Party until the sun comes up?
Mix with the locals and improve your language skills?
If you're going it alone and heading out to find a job with an independent company, you essentially have the final say in terms of where you go. Tour operators will ask you for resort/country preferences, but may not know what resort you are going to until after the training course. Keep an open mind.
Working in a ski resort is very different from spending a week's holiday there.
The high-profile resorts are always highly sought-after, but working there can be far more hectic and stressful than smaller resorts.
Standard of accommodation is usually inversely proportional to the standard of the resort, due to land prices!