Shock horror I'm actually going to praise RM! Not for CC3 which TBH is actually very good if you can afford it and get direct support not have to go through the LEA first, not because the LEA is a problem but they have enough without having to send off all of our issues to RM! I want to praise them for their ISP connection which I know is off topic but damn its been brilliant and very reliable!
Okay back on topic Katem from an unbias view point you have several different options available to you which all will work but have dependancies rooted in cost, time and easy of use. If you want something quick and easy to setup which works reliably then CC3 will be fine sadly at a cost some schools find prohibitive. Ranger again you'll need to setup a few things vanilla system then install ranger on top so time money but a reliable system none the less. LNM (Learning Network Manager) Which isn't difficult to install but many of the functions of CC3 it just doesn't have!
A basic vanilla setup with a few third party products doesn't cost comparatively much but takes time to setup if you plan it right you can get away with a fast installation but I took about 6 months to plan and test and implement which is sadly a little excessive but I wanted to have a "bullet-proof" system I could be happy with (It worked lol)
Many of the guys and gals here can help you with pretty much anything you could imagine, Geoff seems to have an almost encyclopedic knowledge of Linux and Open Source for a start and a very good knowledge of Windows systems too! (He's a real ale drinker like me so I'm bias ;) ) Grumbledook and Webman, Russdev, ChrisH, NetworkGeezer, Bossman, Norphy, Plexer (sorry to everyone I've missed but damn there's lots of you!) there's so many of these guys that make using Edugeek such a great resource if they can't help you it's an exception to the norm! IF there isn't a way to do something some of them will even have scripts and exe's they've written to get round the limitations so whichever direction you decide to go they'll be someone to help you through most of it! Nottinghamshire not far from me so if you really have difficulty I think my school will let me come and give you a hand if you really need it.
CC3 or CSE or Viglen Class for a very easy installation and a nice management console to sort out problems
Vanilla for a very customiseable system
Ranger for tight security
LNM to help the installation of a Vanilla system.