From an administration point of view I personally wouldn't move from SIMs to Integris, it would be a downscale. Integris has many usability features but is rigid on administration and reporting. Take pupil data sheets as an example. On SIMs you can print to a word document and manipulate the document to print on a single sheet. On integris it is printed to pdf and the office staff have to print single sided and staple sheets together. The same applies to labels and many other reports.
I recently moved from 8 years with SIMs to Integris and contacted both to check on development, transfer opportunities, costs etc. Only Capita got back to me. I haven't heard from Integris despite a reminder. They don't seem to be interested in the administration of information management and we have moved away from it for assessment and baselines. So what we are paying for is simply to store pupil basic data. Attendance doesn't link directly to school meal register. It has no finance capability.
If you went for Integris you would be ignoring the administration of pupil data completely and causing a headache for office staff. It would provide no benefit to teachers and I couldn't be more under enthusiastic about a software product if I tried. Our council is one of the most under funded in the country and cost is the only factor that we are stuck in the stone age with Integris to the point we are using excel spreadsheets to compile data as opposed to using this fundamentally flawed software.