In order of importance for me:
1. Quantity and quality of titles
2. Clean and well-maintained machines
3. Cost of games
4. Quality of nearby bars/restaurants
5. Overall game setup (for example, does the lack of PDI glass strongly affect being able to track the ball due to overhead lighting? Do any games have ColorDMDs, does the location remove center and outlane posts that come installed in the game?, etc)
6. Overall atmosphere of venue