We're CC3 here. Works very well, and we support primary schools with Server 2003 and CC3 is far better to manage. You can adapt it if you know what you're doing, whilst being able to let Modern Apps/Trainee's loose on it very early with the simplified management tools.
We have Proxy (Smartcache 2) with them as well as the general stuff. We don't buy there machines any more, we have them built and they work like a dream.
Kate, personally I'd suggest CC3 is ideal for someone part time like yourself, without the time a nd resources to invest in starting from scratch.