Wow, what a difference. I too just visited our public elementary school for DS4. We have recently decided that I think we are just going to go ahead with a public school and then if it fails and the school is not working with us at all...then look into something else.
Anyhow, I only visited a classroom for about 30 minutes. It wasn't horrible. I went in and they were drawing pictures about what they did over the weekend. A few tried writing a couple words about their story. Then they went to the rug for a minute and split up into centers. One group went to computers and the others got to choose between playdough, kitchen, or writing. Anyhow, I realized that it wasn't that horrible but the big problem was that it was Kindergarten, and they were doing things Kindergarteners do. I don't know if I was expecting to walk in and have it be at a 4th grade level and appropriately challenging. I work in pre-k's and K's all day long so I should have completely known what to expect.
The teacher did talk with me during centers and she seemed to have good control of her classroom in a calm focused way. She seemed good, but I could tell not completely knowledgeable of gifted children. She said a few dumb comments, but most were pretty good and supportive. She said that we should do our testing and share it with the school, specifically with the principal and psychologist so we can plan the best set up and services for him in their school. I am trying my best to stay positive and to not assume it is going to fail. But it is hard to imagine my DS not getting bored and acting out in a class that is learning letter sounds and counting.
I would suggest setting up a time to go and see a classroom during the day like I did, and to speak with a teacher. If you talk with a principal or someone first they will probably set you up with a teacher they feel would be best. Good luck.