I'm giving a thumbs up to the Givi E55 ('cause that's how I roll). I originally had the Givi mount with the side struts and all, but switched to the Phil's setup and find it just as secure, with a cleaner look and a lower profile to boot. With the Phil's rack the whole case sits about 1-inch lower than with the Givi plates.
Aesthetically, I think the E55 look great on the C14. There is something in its proportions that looks "right", and I like the capacity. I have been (mostly) careful to mind the 22 pound recommended limit, and find it has minor effects on handling and feel. I tend to carry a lot of photo gear and such, and the larger case lets me toss in quite a bit of gear (like lightweight carbon fiber tripods and the like). I can stuff my 'Stich 1-piece in there when needed (Roadcrafter Light) along with the other tchochkes that end up coming along for the ride!
Rode coast-to-coast last summer, in all kinds of weather, and had no problems, no leaks, no worries.
Just my 2¢ worth. Actually, free advice, worth every penny!