I have had the V-Lux 1 for about 8 months &, altho it hasn't gotten a heavy duty workout (traveling in rural China & Tibet), it has done well so far. I'm off on assignment next week in northern Tibet at 4500 meters (and more), so we'll see how it does in that kind of light along with the dust & dirt.
I've had no probs capturing birds in flight at the extreme telephoto end of things, never a very easy shot for a camera. In the past I've been (most recently) using an Olympus DSLR along with 3-4 Zuiko lenses. The Oly's chip is certainly better & is also bigger (better in low light/higher ISO), but it is a pain to carry around all those lenses all day in rough conditions. My Oly is also faster to focus, but not so as to make any difference that is material.
So there's my take: high convenience factor, mostly useable shots (as long as ISO levels aren't stretched), a fantastic lens (which is relatively fast for a long zoom). The sensor is smaller than the D-Lux 4's (Add D-Lux). It's got more versatile glass (Add V-Lux).
I'd say the D-Lux is a great back up camera, but I wouldn't choose it as my main tool. The V-Lux can be more than a backup camera.
Play with both; see what you like.
This shot is right out of the camera, with no post processing at all. f/5.6, 1/320th/sec. Max telephoto.
