I think what monty is refering to is the fact that there have been lots of people lately post things here like "I'm rich, tell me everything there is ever to know about recording in my million dollar state of the art studio" or something similar. I don't think that's the type of post you intended, so I'll try to answer your main questions. You might want to watch those open ended questions such as "Tell me everything I need..." though.
Personally, I think you would be better off with a computer if you have other uses for it in mind besides recording. You could get a workable computer setup for about the same price as the 1680. Sound quality between a good computer setup and the 1680 will be about the same. The computer will give you more options in both hardware, software, and future upgrades. Edtiing is easier on the PC. It won't be as portable as the 1680. If you are looking for an all in one, portable, buy it/plug in/start recording solution, then the 1680 is a good machine. If you want a computer for other purposes and also be able to use it as a good digital recording setup, then by all means the PC can handle it.
Now, if you want any more info, just ask specific questions and I'm sure most people would be glad to help. Search the BBS for things such as what sound card options you have concerning the computer and you will probably be able to answer your own questions.