Best iPhone app for MS Word viewedit w external keyboard

D2Go and QuickOffice are the two everyone discusses (and Pages a bit). Most conversations veer into excel editing & pdf viewing, which I dont care about. Me, Im mostly interested in word processing with MS word docs sent to me by email or which I will create/edit on the phone and send back and forth to people working on PCs or Macs with the MS Office suite. Extra points if track changes & comments functions work. Also -- and important -- Ive got an apple bluetooth keyboard that I will be using and so also want it to work well with that. Any advice? Thanks.
iPhone 4