simply put, the best facility around, i moved out of illinois 2 years ago, and have since played at fields in texas, oklahoma, and southern arizona, and even the fields that are considered the best in these areas do not compare to what chili had to offer. in terms of field size, variety, development, and staff, you cant ask for much more.
the biggest advantage chili has is its size with more than 40 acres and 6-7 different fields you never have to play the same setup twice in a day. also, you will find that they have a great balance of natural terrain and man-made bunkers/obstructions. EVERY field that i have played at since leaving illinois has followed a similar formula of at best a 5 acre area littered with bunkers - may as well be playing in a junkyard. also whereas many fields only have enough area to offer 1 or 2 different scenarios a day chili has mulitple fields with even more possible forts/starting positions and the staff does a great job mixing up the scenarios to utilize the entire field throughout the course of the day.
the only downside to chili is the number of newbies present at any given time - as much as i like to see new players, particularly players enjoying and learning the core of paintball (as opposed to being speedball junkies) the sheer number of inexperienced players -that come with any commercial field - can make it unpleasant for experienced players, namely when you are shot by your teammates, shot when you are out, or have to deal with the occasional problem child who wipes paint instead of calling out.
while i have not been back to chili in the last two years, having known the staff and ownership for the 7 years that i did play there regularly i can imagine that things have only improved as the popularity and local support of the sport has increased.