I have a Ducky Shine II, a Ducky Shine III, and a Deck Francium Pro, so I guess I'm fairly qualified to comment here.
Which is better? That's very subjective of course, but for me it's the Francium Pro, despite the oddness. But that's because it scratches a certain itch for me, namely being one of the few keyboards on the market where you can program your own lighting effects.
This means you can program any effect the Ducky can do, and much more. It doesn't currently support reactive lighting effects (except the built in ones) until an upcoming firmware release adds it, so it can't quite match the Ducky's reactive modes at present.
If you're not a programmer though, then the Ducky is the better option. You can do individual lighting on the Francium as with Ducky's custom lighting mode (where you tap the keys you want lit), but you currently have to write a script to do it which is an extra step that may annoy some. One advantage to this is you can then set the individual brightnesses of the keys you select, whereas the Ducky's are always full bright. One of the scripts I wrote made the WASD cluster full-bright and the alphas very dim, with the rest of the keyboard's LEDs off. This way I could find WASD with the lights off, and still find the letter keys for typing in-game messages.
On the construction quality side, well, both seem fine there. I quite like the Francium's faux aluminium look, for those of us that can't justify the price of a real one.
As for the Deck's key-caps. *cough* Well, I tried to like them, but only lasted a day before I ripped them off and replaced them with Ducky ones. It wasn't just the weird font; they're supposed to be back-lit keys, but they really don't let a lot of the LED's light through. In daytime I couldn't see them at all, which is a problem when they're used to indicate caps-lock, macro mode, etc. They were also my first PBT keys, but I admit I don't see what the attraction is of them. I prefer the Ducky's ABS keys.
Oh, one other thing. The Francium has a programmable macro layer, very much like the Poker II, where you can program in a series of key-strokes and delays on any key of the keyboard, something the Ducky can't do. You can even save them to disk for loading in later. This wasn't much of a consideration for me as I haven't found much of a use for that, but it may be a nice feature for others.
The Francium is currently the board I use the most, but my Ducky's aren't TKL boards, and I've definitely learned that TKL is my preferred keyboard style. However, I think I'd still use the Francium if the Ducky's were TKL as well, simply because I can customise the lighting to just how I like it.
Oh, and the Francium comes with a key-cap puller that doubles as a bottle opener.
Hope that helps.
