Not to discount the personal labor cost in transitioning from Mac --> PC, and in babying two platforms, I just wanted to point out that the
HP 2710p Tablet PC is now quite cheap refurbished from HP ($600-700), as is the newer 2730p ($1,000-1,250). The 2730p adds a scroll wheel, which is desirable when reading in portrait mode, and a scrolling pad when typing, worth the difference to some people (I'm a 2710p owner and wish I had those two features). But you must add in anti-virus and $70 for
PDF Annotator, which is great for handwritten annotations. The 2710p refurb is competitive in cost with the DR1000S. OK, not nearly as light, but with color annotations (what's a professor without a red pen?)
These weigh less than 4 lbs. and have battery life around 5 hours, with an available slice extender battery that gives all-day battery life. The dock with built-in CD/DVD costs extra.