As a non-player I would have to say that I look for the bathroom facilities to have the hand sanitizer in each bathroom. Also, to have toilet paper and smell reasonable.
If the paintball field has picnic tables, I look for them to be in good condition. Also, to have some covering for sun and/or rain.
I also look for good prices on food and drink.
I look for the staff to be friendly and to keep safety a priority.