Ok, a promise is a promise and now I got a few dives with the Luna (and can compare with my Suunto Stinger).
The Stinger is obviously practical as it's wrist sized, but in all other terms (ie diving-wise) I must say I like the Luna better: very easy to see UW and I like the RBT indicator as well as little details such as the safety-stop countdown. I've tried the various display options and prefer the standard "medium" option as the "full" is almost too cluttered for a no-deco dive on air. Took a little while to figure out that the RBT is related to the reserve, not to zero, so you may want to adjust reserve down from 50bar... And the log is a pleasure in terms of information and simplicity (whereas e.g. the Suunto Zoop is a tricky bugger).
So, in conclusion: if you want a DC and you're a Rec Diver and don't need the wrist-sized variety, at least this diver is very happy. Judging from this thread there are obviously plenty alternatives, but having looked into quite a few of them - at least in Europe this seems (to me) to be a very good cost/utility ratio.
Best, R