With all the stumbling blocks associated with changing ISP, There are ways around everything. In another school, Link2ict were forced to setup a VPN to collect data and provide support and such like after an ISP change. It's up to schools whether the inconvenience of other things is worth the saving. If you have a good ICT support in school, there's really not much need to contact them. I certainly don't day to day.
I'm not saying don't go with Link2ICT at as there's some parts of the subscription that are great value fo money.
The important fact is that schools shouldn't feel like there's no choice. Remember, Link2ICT are a limited company and as a result, have to turn a profit like every other comapny. Budgets have been cut, sacrifices have to made.