Sometimes I use Office 2000 under Windows2000 under Virtualbox, and it's amazing how snappy the apps feel when the whole VM has only 64MB of RAM. Everyone should try it once in a while, just as a reminder of what is possible!
The only Office app that I strongly prefer in its modern form is Excel. Modern Excel has some really nice enhancements (sequences and spillover, let and lambda, flash-fill, table formatting, etc) that I miss when I use older versions.