Okay, so basically.. here is how it works. So, lets pretend you have only one 1H weapon. With that 1H weapon you have a 5% miss chance that's just base level. Now, getting a dual wield lets you use the SECOND weapon in between the first hits. That's how the game interacts with it. What I mean by that is, if you were to remove your second weapon, nothing would change between how much or how fast your first weapon hits. Okay, so now we know that the second weapon moves independently to the first. Now, getting a dual wield makes it so that each weapon has an additional 19% hit chance (as a penalty). The idea here is that because you now have two weapons that can do the same amount of damage EACH as one of them would do, you have to give some sort of miss penalty or else dual wielding would just do insane amounts of damage.
Now, that brings us to why we would want to dual wield. Dual wielding is a lot of "fast" damage. 2H on the other hand (due to slow speed) hits much harder, thus much more "burst," but is not constant damage. This is important because it gives you choice. If you have two really quick 1H weapons, you are not going to be getting giant white crits, but it means that you are going to be whittling down health constantly. Slower weapons, on the other hand, hit less often, but much harder. So, when you have two 1H you get a 19% chance to miss + 5% PER weapon. That means in total, you have a 24% chance to miss. That means that in most cases hit is king for wielding two weapons as it means you are hitting more often. Thus, you sacrifice other stats (agi/str) for hit in most cases.
Edit: 24% is for PvE. 8% is for hit cap for PvP apparently (white dmg). Still checking sources on this though.
As for which one is better - it really is up to you. 2H Fury gets really big hits (as per Budson) but it also means that with a constant healer, he's not going to put out the pressure he needs to. Getting two 1H'rs means constant damage (which can be helpful if you are only on target for short amounts of time. Personally, I would dual wield if I didn't have a healer or a mage (or someone else that can slow people). If I was reliant on only my ability to close gaps it doesn't make sense to rely on big crits that I might not even get. If I do have a healer/slow (arena) I would probably go with a 2H