I guess I don't live around 96+% humidity much, so I really don't care.
I know Davis stations are expensive, I'm still not upgrading until the 3 comes out or I die, and then my wife will put on on the marker when they do.
But face it, for all the functions they provide, at a premium, there are few alternatives that are integrated and are wireless and last up to 14+ years (like my original VP) and still be darned close, what do you expect?
Texas Weather has some old stuff that keeps on cranking since they were built very well and tough and their temperature/humidity sensors are pretty close to every thing else. The only thing that is very consistent and as far as I an tell repeatable but then again I don't have a humidity cabinet, are the Vaisala WXT500 series. Their rain sensor is a bit weird and they caution that it isn't for research grade observations but I have a (used) 510 and a 520 that cork along putting out temperatures within a 1/2 degree of each other and the humidity is within a percent or two. The highest I've had was 99% on one and 98.7 % on the other one. The barometers track within a few 0.001 in pressure as often as I cross check them. Get out a checkbook for a (new) one in the range of two grand. They are by far the most consistent tracking with themselves or the TWI or the RM Young stuff. There are some lower teir professional stuff that runs into the two to five grand figures, with a temp/humidity HMP333 from Vaisala as part of that for a couple grand with the goodies on board.
I think that Davis is expensive. But buying a couple hundred dollar grade school system a few times adds up, too. My $1200 Rainwise MarkIII is now showing me 100% and when it is lower humidity, it is pretty close to the other stations, all located on my 5 acres of property.
I learned long ago that the rain measurements were a bit of a variable, too. The (used) tipping buckets that run $300 to $500 new are never equivalent, even though within a few feet of each other on the same surface and height. And compared to the open collector (without the wind dress around the outside to shield it, which aren't at all the airports, either) there is always a few hundreds of variation.
I guess that while seeing this is one of the most active conversations on this thread, and with some really cool comparisons by some dedicated observers, I can't see faulting Davis for using the best they can get at a competitive price and doing quite well. If they have packaged or shipped their new replacement sensors incorrectly, then folks like Scaled and Ambient need to complain that their customers have discovered a problem with Davis' packing and shipping, along with notes from the dedicated users here who have done the testing.
But after I read the specs for RM Young, Vaisala and other pro grade devices, they all say there is a known drift per year, and give graphs showing how much it might be. And they come (new) calibrated with a sticker saying when the next calibration is due, if you can afford it. The Vaisala WXT510 and 520 I have would run about $500 each to be tuned up. My Met One ultrasonic wind sensor would be a $150 charge to just ship it in, and then more on top of it. So when someone tells me that a $20 chip won't stay in calibration for a year or so, I'm not too put out.
I wish they'd say how to calibrate them rather than sending them back, with which screw to turn to adjust the slope and which to adjust the intercept, but then you'd need a closed chamber with a large bath of various salts to jump back and forth between to do it right. I don't want to have the wife mad at me for spending the equivalent of a brand new Davis or two a year just to get my stuff re-calibrated.
I do note that one of my Vaisala's is no longer in certification (by about a decade) and it is within a few percent most of the time with all the other humidity sniffers I have. Even though it isn't perfect, it remains a stable workhorse for me.
But I'm not a university or have a government grant so I'm thinking anything from Rainwise, to Davis to Texas Weather is very cool to have, heck even the Peet Brothers that I have compare far closer than I thought based on what I paid for them.
Sorry to seem a bit touchy, but you buy a $400 cam corder don't expect to get Spielberg or Stanley Kubrik production quality videos, but the kids and grandkids still look so much better on the HD from the cheap camera compared to the really expensive prosumer stuff. And the prop blades on airplanes or helicopters still are bent.