I initially decided on Doug's, but when I got ready to get them on, because of their geometry, there just wasn't enough room to put them where I wanted them to go (installing on a Bassini y-pipe). The Doug's looked solid but were not completely stainless. I could see how the heat might warp them and make them stick but I'm just guessing since they never got put on and are they're still sitting in the box. I went with QTP which are fully stainless and a little more compact...they have worked great. I don't have to deal with any salt issues so I can't speak about that.
The one complaint I have about them is the cheap-ass wiring connector at the cutout. If you get these, the first thing you need to do is cut them off and splice in two-pole, flat, trailer connectors.....WAYYY better.
Someone also asked about horsepower gain, cutout vs. no cutout. I have not dynoed mine with the cutouts closed (although it would be interesting to know). I have a TT setup and the difference between closed and open is a good 2 lbs difference. In other words, if I set it up to run at 10 lbs of boost with them closed, the boost will jump to 12 lbs with them open. That's 20% more boost by doing nothing more than running the exhaust about as close to dumping at the headers as you can get.
Closed, it runs through a standard Roush cat-back (of course I have no cats), and it sounds good but reasonably docile. With the cutouts open...It's ridiculously loud. It makes the ground shake when you're in it...and literally scares people when you go past them on the interstate.