I can't decide between the m3 entry model or the i5 with 4Gb of RAM and 128Gb SSD. I can't afford the 8Gb/256Gb version of the i5. Reviews seem to compare the m3 with the 256Gb i5. I use MS Office (including complicated Excel files), Word, web browser, Outlook and Sage simultaneously. Should I opt for the i5 for £100 more or will the m3 suit my needs?