Pros
There's nobody watching over you and you pretty much have free rein to come and go as you please, if you are so inclined. Generally, the techies are the salt of the earth, battling daily in vain against dogma and obstruction
Cons
There is no backup, no technical support, no clear lines of escalation. Basically if you have a technical problem you're on your own, and although they claim to have 55% of the UK Windows installations they don't have an account with Microsoft. In a multi-vendor environment, CC takes on all the rubbish that other vendors can't or won't handle. They give this service away free, thinking it will gain them customer respect. Don't be surprised if you end up as a part-time van driver when you thought you were an IT specialist.