There are niggles with SoftMaker components - particularly opening Excel 2003 files (I also recall an issue or two with Word documents but can't remember specifics, so could just be a trick of the memory!). The far bigger issue in Chris' case is layout and menus - that's where Star/OpenOffice are more "like" MS Office and would, I think, be easier to provide assistance with from afar. Having said that, I'll stress again that for light footprint and general usage where the level of computer knowledge (on the part of the user) is good, my vote would go for Ashampoo/Softmaker as well. Their stuff is really well thought out and presented, the support forum is active and frequented by support staff, and the product is actively developed, which means that bug fixes are released quite frequently.
Of course, for a PhD candidate whose needs extend beyond simple word processing, I would HIGHLY recommend MS Office Student and Teacher edition, simply because that will result in the least amount of compatibility issues when sharing files with fellow students, supervisors, submitting presentations for conferences, etc, etc.