Summary: I had been searching around for a used projector for quite a while, trying to find a brand name I recognized without spending over $500. The 3M S10 was a great choice. It Is very bright, easy to see in even a somewhat lit room. It only has a 300:1 contrast ratio, but after some research, I learned that contrast ratio is one of those numbers manufacturers try to balloon up to make their product look better than it is. Much like Gigabytes in hard drives.
Summary: Personal Experience As a teacher, I've used the 3M S10 LCD projector for five years now. I use it most days from 8:20 AM until about 3 PM, Monday through Friday. It is very reliable and has nice features such as a remote control with zoom. It gives visible warnings when the filter needs cleaning and when the lamp is nearing its useful life. The S10 has good resolution in small and medium sized rooms. We used it in a ballroom once with good results as well.