There is a lot of negativity sometimes on the board - and its not hard to understand. There is a trash problem and too many don't use the place responsibly - leave no trace, pack out what you pack in, camping, fires, etc. But I'm also always amazed by the positives - many who post here and others who don't who do amazing amounts of work down there, cleaning, caring, making sure things are right with the springs area. The place attracts wonderful and beautiful people, almost every time I go I meet someone great. Many will take out a trash bag and clean broken glass or hike out someone else's trash. Sometimes people make beautiful music. They share their drinks and food. The conversations are mind-opening.
On your question I always try to go on a weekday. More mellow vibe, less partying usually, and more being one with nature which is how I like to enjoy the springs - nude. Thursday and Friday most often are my days. Strangely last time I went, from people I talked to, Wednesday turned out to be a crowded day with lots of campers, Thursday was mellow and just right, and Friday was empty, mostly. Like I literally had the springs to myself for 3 hours at least. So it changes all the time.