I have seen a few comments about Bromcom MIS which we have been using here for some months now. We chose it over Serco or Sims due to it being a new product, from a relatively small company, that was willing to develop it further in partnership with us and apart from a few problems at the start importing data from Phoenix Gold, it has worked very well.
The data is all held on our server in school and updates are carried out remotely by Bromcom as required. No changes are needed to staff laptops or workstations which link to the server via the web interface.
Support has been second to none and I have lost count of the number of on-site training days we have had. Staff are very pleased with it and a lot of time is now being saved, especially with student reports, which will automatically link into the parents portal MyChildAtSchool, as will the other modules we use such as attendance, behaviour,etc.
U/N and passwords are now encrypted and no longer viewable in Notepad!
Even if you still use Sims I would recommend getting a demo of the MyChildAtSchool.com
web portal which is so simple for parents to use.