Our two cents worth...
We started cruising way back in 1990, before any of these wonderful systems were available.  We've gone from LORAN to GPS and weatherfax to grib files.  A few years back we started using ugrib, obtaining the files via wifi when we were coastal cruising in europe, supplementing with weatherfax when offshore.   As we move into the 21st century (ok we're a little slow), we definitely see the use for a version of ugrib on the pda.  Many times in harbors or small towns it is difficult to find WIFI, especiallly for those of us on a tight budget-looking for free access,  currently we carry a laptop around finding a sight and downloading.  A PDA would be infinitely easier - less weight, easier to shield form the rain (or snow).  We are buying one this year and plan to use it in conjunction with saildocs to get the file via email, transfer it to the laptop and view.  Wouldn't it be nice to not have to go through that extra step??
Incidentally, we have been cruising europe for 10 plus years and, with the exception with offshore passages to Iceland,Svalbard, etc.. we have nearly always been able to get cell phone coverage.
Thanks again for the great product!!!