I went mid-week and had many runs completely to myself. It was raining in the morning when I arrived, but the sun came out around lunch time and it turned into a fantastic day. I had a bowl of rammen while waiting for the rain to subside (900 yen for a bowl and not bad.)
The staff were friendly the runs were perfect for me, as I'm a beginner. There were a few advanced runs, but most folks stayed on the general ones, which had the jumps and grinds.