I am a new user to this forum, and am a little disappointed to see some of the posts on this thread, however, I would like to balance the argument slightly, I currently support 77 schools and have implemented ranger on over 30 of them, we have developed an excellent relationship with Sentinel and I am a fan of their product.
That said it isn't for everyone and there are pros and cons with any implementation. Don't rule it out though, it's an excellent product with some good developments.
If you would like to know more about our experiences in North Tyneside LEA then send me a message or give me a call and I would be happy to discuss it in further detail.
Rob.