I run a Ranger 198vx with a 200 Optimax, (same boat as the old 518/519, they just changed the name) and it does fairly well in rough water. It won't beat you to death if you can drive it right, but it ain't like riding a larger 20-21 foot boat either. It really helps to know your limitations as an operator and the limitations of the boat. I have been in some pretty bad stuff and I feel safe in the boat and in my ability to operate it.
Now as far as fish-ability, stability, and performance, these boats are hard to beat in the 19 foot class. Don't expect to run 70+, but high 60's and right at 70 are achievable if set up properly. I can run 67-68 all day long and not have to really "drive" the boat to do so. The boat trailers really well and is really easy to load. And the Ranger Boat Cover has got to be the easiest to use.
Couple of things I am not really fond of is that the dash isn't fully molded like on a Legend or Basscat. Aesthetically this okay, but plan on changing out the screws that mount the panels with bolts. I opted for a dual console for resale value, but you will have a harder time getting longer rods in the rod locker, and longer rods on the deck will end up riding down on to the console.
As far as everything else, I have been really pleased with the boat. Fit and finish are top notch, exactly what you would expect from Ranger. I have fished out this boat with two other people comfortably all day long, without a lot of noticeable rocking. And with the 200 opti, this thing literally sips the fuel.
I don't think you could go wrong with a 518 Ranger, a Pantera, or a 200zx. They are all different, so it really goes down to your personal preference. Can't say much about other brands because I haven't fished out them.