I've got one of the CZ (Huglu) Ringneck side by sides in 28 ga. that I bought new in 2006. I'd been looking at the Huglu and DeHaan (Huglu) guns and when CZ picked up the importation and marketing of the former Huglu line, I jumped on one. A friend of a friend in South Carolina has a 410 that my friend (a gun guy) says is nicely put together and shoots good.
I haven't seen one of the DeHaan versions in person but I spoke with the company when I was shopping for a 28 SxS and they were very helpful over the phone. Their record of customer service seems very good.
The original Huglu's had at least 2 importers/distributors and some QC issues. Worse, warranty coverage didn't carry over, which left some folks stuck with problems.
As for my experience, I've been quite satisfied with mine. It's a lovely little shotgun and I've had no real trouble with it, although I confess I've only shot a couple hundred rounds at clay birds with it and hunted grouse with it last year and this. I did kill the first grouse I shot at with it, which endeared it to me forever. It's since killed several more and I seem to be as effective with it as anything else (that is to say, grouse only embarrass me most of the time), but it sure looks classy! I have several other 28 ga. guns and typically hunt grouse with either a Browning Citori Lightning or Remington 870, both 28 ga., so I guess it's a fair comparison.
I wanted a single trigger, which the Ringneck has, and I particularly like the length of pull and the rounded 'Prince of Wales' pistol grip. It came with 5 chokes, which seems silly to me for a 28 ga. SxS. To my mind a SxS or over/under sub-gauge gun ought to have fixed chokes. Mine has the 28" barrels, which is all the store I bought it from had in stock. I liked the feel of several 26" Huglus I'd hefted but I probably shoot better with the longer barrel.
I've read about some folks having problems with the safety and (maybe) having it repaired/replaced under warranty. I haven't had a problem yet but the safety does feel quite rough when you switch from barrel to barrel. If you search back through the archives in this thread you'll find some discussion of the issue.
I don't know what they cost this year, but when I bought mine you had to pay MSRP or even a bit more. I think they're about the nicest looking and maybe the best deal in their price range. They certainly are a step up from the $500-600 SxS choices, but still only something like half the price of most of the European "entry level" SxS guns. Good luck. -WSJ