I just passed the decision making process myself and bought one. I previously owned (actually still do) a Sharp 5500 and also tried other PDA\'s.
Although I am not a linux expert, The reason I decided to stick with Sharp/Linux, plunk down the huge $$, and go for an \"unsupported\" import is:
1) The relatively few people that know this machine, KNOW this machine...I mean your amount of expert help is phenominal. (except me of course). So support is not an issue...warranty works but shipping is costlier than domestic.
2) I discovered once I setup the 5500, I rarely needed to update it and/or go out on the web for more stuff. Right now I am in the midst of configuring it exactly for my needs...making sure it does all I want, and as well as I need it to do it.
3) The raw functionality and capabilities of the machine are amazing. That coupled with item one (above) means that if you have a good idea for something, someone is probably already doing it or porting it....or might if you ask.
4) I love my 5500, but with the low resolution (which was already bigger than most palms) and lame keyboard (again most palms don\'t even have one) I deceided that although I am spoiled by having two features better than the palm, I wanted them even better than that. With that said, the screen and keyboard are FANTASTIC. This much I KNOW you will love....the hardware ROCKS.
My conclusion so far (while I am in the setup phase) is mixed. I switched to CACKO QT ROM and I highly recommend it (you can overclock in a snap and it\'s got nice bells and whistles...and you don\'t have to learn anything new...looks like Sharp\'s ROM but better).
My main concern is a lack of native (Landscape) games, lack of a good alarm clock program, and the seemingly lack of it\'s ability to play movies as well as my 5500 (I know that last one seems very strange, but my 5500 plays movies very well and so far I haven\'t gotten anywhere near the performance (frames per second)...but remember the screeen is FOUR times larger and the processor is only TWO times faster).
These issues are really specific to me, and I am confident I will solve them to beyond my satisfaction. As for you, the c860 seems to fit the bill for you right out of the box. The hardware alone is worth the added convience and the word/excel functionality is right there (although I have no idea how good hancom is, becuase I have yet to use it much, but it sure looks the part).
Hope this helps.