Broadway - very well done with some of the lead talent brought in from throughout the US. From time to time they have a former Broadway performer in the mix of shows as well. Much of the talent is local - especially for the kids/youth roles which are usually brought in through Tuacahn High School.
My advice is to bring one of those neck-cooling towel things and a spray bottle with a fan. It gets hot - usually in the 80s or 90s at Showtime. It cools down to light-jacket temps if you go near the end of the season in late September or early October.