Oh Lord, that covers an awful lot of ground. The 14 is one of my favorites, but at 7-1/2", be warned that it's a pretty big knife. I guess the first thing you should consider is stainless steel versus carbon steel. Most everyone I know prefers carbon steel, but if you live in a place that has high humidity or plan on using the knife in wet conditions, maybe stainless will be a better choice.
Will this knife be a "user" or a "safe queen?" If you're going to use it, you'll probably be better off sticking with the Micarta handle that comes with it at no extra charge. You still have the options of going with the stock finger grips, a Border Patrol handle, or a single finger grip handle. All are good, all are slightly different, and a lot of the choice comes down to just personal preference.
If you want to get a little more fancy, you can go for a "cut-down tang" version, which opens up a wide array of other options: stag, wood, and so on. You can use shop-supplied handle materials at a modest extra charge, or supply your own at a slightly higher cost.
Nickel-silver furniture is an option on all of these knives too, but it costs more than brass.
There are many other, more obscure, options available too if you want to really go crazy.
The 12-9 is even more of a favorite of mine, but if the 14 is a "big" knife, this one's "huge." Not the most practical thing in the world (and kind of heavy, too), but if you're out to impress someone, it's definitely the way to go. There are a gazillion different options here, too, including a #14 grind in stainless steel, a standard clip-point grind in carbon steel, and even a #25 handle style.
Hope this helps; feel free to ask any more specific questions you may have. I'm sure others will chime in with their opinions too, and maybe even some photos.
