Wasn't overly impressed with the accuracy of this device. ...
937473
Wasn't overly impressed with the accuracy of this device.  Seemed to be off by as much as 5 degrees (after conversion to F).  Could have been the particular unit I received.  Hard to say.
1499998
I had high hopes for this item based on its positive reviews but it let me down. I know that getting close to milligram accuracy out of a device like this would be nearly impossible and I was prepared for that. What I wasn't prepared for however is a device that seemingly pulls random values for mass out of the ether.

I first attempted to gauge the mass of the 10mg calibration weights that the device came with. Upon weighing both there was already a several milligram discrepancy between their printed weight and the reported weight. No problem, things rarely come calibrated correctly. I then attempted to calibrate the scale as instructed in the manual, everything seemed great, so I power cycled the device to make sure that this was going to stick. Upon testing the first weight I got a measurement of 7.3mg (within tolerance) and the second weight at 13.6 mg (also within tolerance). Now here is the kicker those two weights that are supposed to be the same 10mg mass are now more than 6.3 mg different. When I stack both weights they come out to a measly 12.4mg.

Oh well, at least I have paper weight.
545972
The product takes some getting use to. It will give false readings at times which are distractive enough. The ON/OFF switch is extremely sensitive and will turn on at the slightest touch. The unit is accurate roughly 2/3rd of the time, so I guess for the price paid not terribly bad. Disappointed somewhat-especially with the microprocessor inside not providing reliable results.
2588106
It really isn't accurate. Sure, once you count all the money and then double check it, it seems to know, but it's a 50/50 chance it'll be right. Whats the point of using it if I still have to count it all myself? Should've bought a better one. Great if you just "generally" want to know how much you have, but forget accuracy.
2328194
My head was telling me that this unit is too cheap to be an accurate instrument, but my heart said give it a try.  Well, I should have listened to my head, because I found that I was not getting accurate or repeatable temperature measurements.  If your looking for a toy, this one's for you, but don't expect it to be any more than that.  I returned the item.
3680671
Accuracy does not appear to be as good as for Home, version 12 for Windows. I have concerns that it may be slowing down my computer.
4866140
Okay, so I purchased this because of reading about what a great detector this is. But I'm not sure it's really worth the money, the machine is slow, I know it has a powerful processor but come on, I pass over a target and it stays on the same reading after I've moved on. The pin point seems to be a bit off as well.  I've had much better luck with my Fisher than I've had with this.  Maybe I should give it more time or maybe I should put it on Craigslist and try to get some of my money back.
4320309
The jury is still out concerning the accuracy and time is takes to settle down. Sometimes I don't know if it's telling me the truth because I'm in and out of a customer's home so quickly and can't afford to wait for the tool to settle. It is still appealing to me, but I would get a device that reads quicker if you really need those checks.
4406323
The principle is not new- so the price was very appealing - unfortunately, the accuracy was not- I was having refrigerator issues and trying to get an accurate interior temp- the reading I got was 10 degrees lower than what registered on the  expensive meter the tech had-
Just to make sure (this one said refrigerator was at 27 degrees) I left a bottle of water in the "27 degree" location for 3 days- not a sign of ice- so the Tech's reading of 37 degrees made much more sense.
It went back....
2540839
Not as complete as I was looking for.  A bit difficult to use...Not as accurate as expected.  For something VERY basic, I guess this would do.
1812240
Very disappointing as far as accuracy goes.  A basic Fluke 115 meter has a +/-0.5%+2 accuracy (dc voltage).  Redfish's iDVM advertises a +/-2%+2.  This is horrible for a $240.00 meter!  You can purchase the Fluke 115 all day long for around $150 or less on eBay.  I understand that Redfish introduced an wireless meter for your smartphone, but competing, stand alone meters on the market don't add that much space to your tool bag and they give you much higher accuracy for a lot less.  (And when your "meter" rings, you don't have to interrupt your measurement)
2302743
Disappointed or maybe I expected too much from the product. I initially bought it to keep track of my activity during a normal workday. But after trying several times(unsuccessfully) to get calibrated, I just gave up. It counts steps, ok scratching my head isn't me stepping/striding.
1343514
Not all that accurate as compared to my blood pressure machine.  I would return it if it was possible.
4326807
They work - but if you are seeking some real accuracy then these are not the best solution.
2882910
I bought one of these and found its readings to be off, so I assumed it was miscalibrated and exchanged for another, but it's the same. It's just not that accurate. I find it to be off around 10%. For example, my car tire pressure, knowing that my air compressor is set for 35 psi and my car tire monitoring system also acknowleges 35 psi, this thing will read 29-31 psi. It's not accurate enough IMO.  I find it less accurate than a cheap sliding gauge.
2107684
Purchased unit to monitor moisture level in guitars. Unit was well priced but not very accurate ( +15%) compared to several other hygrometers I own. I wish unit could be calibrated
2141566
Not totally happy with this device, but I think it's accurate.  Even just sitting in my had prior to testing the display reading was jumping.  It doesn't just take an instant reading like a TDS Meter, rather it seems to slowly, slowly, slowly blip up or down to what the actual pH is.  And it can take a few minutes.  For example, if my solution is 6.0pH in reality and the meter touches the water showing 7.0pH, it will tick on down every so slowly (did I say slowly?) until it hits a mark where you must finally draw the line.  HOWEVER if the meter starts BELOW your pH...say for whatever reason it touches the water and starts at 5.0 pH, it will rise quicker and your reading will stabilize faster.  After testing the "Bring the number up from below" produced very consistent results.  Gently shaking or very gently tapping the device when in the solution seemed to make it "reset" to a lower number.  I might try drops or strips in the future.