I first saw the platinum CDV in Watches and wonders 2015 here in Hong Kong (RIP to the exhibition), that's easily my favorite piece in the entire exhibition. The case was sensual, the blue on the dial popped, and I really liked that VC had upgraded from the 1141 movement. I only didn't pick one up because I'd just bought a manual chronograph in platinum couple months ago- the Dato 1st gen.
So yes, I'm somewhat biased. Among VC, Patek, and Lange, my preference is Dato, closely followed by CDV, then the 5170 with quite a bit of distance.
Dato is special, as many have said, because it revitalized the chronograph complication. The criticism on its uneven proportion is fair, but I find it comfortable enough on wrist (I tend to strap it tighter than I would with my other watches. Wouldn't want to knock around the platinum case, and I like the secure feel for a head-heavy watch.) It's just about finding the right fit.
The CDV continues to be a goal. I'll likely go for the RG version, which I find warmer and it'd better compliment the Dato in my collection. Christmas can't come soon enough...
5170 is a fine watch. Unfortunately it just doesn't provoke much emotion for me, perhaps it's missing some extravagence that I found in the Dato with its movement and the VC with its case.
Ken