It's easier to learn that ASL or BSL and can be understood by those who know both. It's commonly taught to those with developmental disabilities who have little or no verbal skills.
I strongly have to disagree with this. I know the primary author of the SEE book you are referring to. The theory behind see is to teach Deaf kids English... so there is theoretically a sign for every word including "a" "the" "and" and endings like "-ment" "-ness" "-ly" "-ing." It's a made up sign system... like the Makaton system I linked earlier in this thread.
It may be easier to learn for English speaking adults because it follows English word order. I worked after school in the school where this method was used. As a fluent ASL user, I had the hardest time understanding the kids. I had to have my colleague interpret for me many times! Instead of being able to express themselves freely and creatively, they were bound to expressing themselves in Signing Exact English. It took forever to get their point. This argument is too broad to make on a message board. Yes, it works for some... but more often than not SEE is lost to ASL as they get older.
Also cultural implication... SEE doesn't have the roots that ASL has, deaf schools, deaf culture etc. ASL like BSL, et al, is a proper language. It has it's own syntax/sentence structure.
Not to mention that many of the signs are just ridiculous and are not conceptual.
