I have been using this a lot for close to a year now, and in all that time I have not found a single drawback with it. I mean SERIOUSLY - I even thought of the color of the plastic case, but it is a nice bright red, with substantial hinges and they work well. The well for the tool is even lined with foam inside. The batteries? Well there are two inside the box and one in the caliper when it came. As long as you remember to turn it off, or let the auto off do it's job, then I have not had to change the original battery in almost a year now.
The caliper itself is a stainless steel, but it did become slightly magnetic when measuring the dimensions of an N52 super magnet. Even that magnet failed to interfere with the electronics and it behaved perfectly, keeping accurate readings throughout.
I know some reviews say that it needs to keep being zeroed a lot. I was afraid of that, but I have had no such problems at all with mine. Even viciously sliding the scale in and out many times, it went back to 0.0000 inch perfectly. I did occasionally get an offset of perhaps 0.0005", but that proved to be a speck of dirt on the measuring faces every time. Perhaps that was the cause of the problems some were having? Just wipe the measuring surfaces with a clean, soft cloth and the problem was solved for me. Even so, we are talking about 0.0005" (1/2000"). It is "only" rated for an accuracy of +/- 0.001" (1/1000"), so that last digit might show a 0 or a 5 and still be well within it's rated accuracy. This is seriously good for a digital caliper.
For me what was a real suprise was just how useful being able to measure in fractions of an inch really is. It reads out in 1/128", but automatically cancels down to the lowest common denominator. So it would not say 2/128", but 1/64" instead. This is astonishingly useful for quick "go" / "no go" measurements, and also it does away with the need for tables to know if that drill with the size missing, is 7/64" or not? Anything with a fractional inch measurement can be read directly, instead of looking up the decimal/fractional tables.
It uses an LR44 (alkaline 1.5V) battery, which are also commonly sold as AG13, L1154. LR1154, or 157 batteries. The slightly more expensive Silver Oxide versions though might be better in the long run, as their voltage is more stable during the lifetime of the battery. Silver oxide equivalents are SR44, SR44SW, 303 and 357.
Reading the reviews for this was disappointing. Certainly Vinca seem to read all the comments and replace faulty ones, but they also listen and update the design. Mine having an auto off feature is a good example, as earlier ones apparently did not have this. My auto off seems to put it into very deep suspended animation, as moving the scale does not wake it up, and even though I have left it in auto off for months, there is no sign of the original battery that was in it having run down.
There seems to be a lot of confusion in the reviews about what digital calipers are, and what they do. That seems to be why a lot of people have only given four stars or less. I think a lot of mentions of them being "sharp", might be that they do not know that the beaks of the jaws need to be that sharp in order to measure accurately in confined spaces - such as the minor diameter of a thread. Also to reduce the parallax errors with some types of measurements. The points are sharp, so that they can be used to scribe a mark onto things at the precise distance you have set them to. Them not feeling "very good quality" might be as occasional reviewers have noticed, that the wheel is "wobbly". This is intentional, as it is meant to better control how tight you clamp them onto the workpiece - Much like the friction clutch you get on micrometers. Engineers know that with measurements this accurate, how tight you make it on the workpiece, can affect the reading. So the whole point of using the "wobbly wheel" is to try to standardise the amount of force that is used to close the jaws and so improve accuracy that way.
Digital calipers of this quality ARE accurate scientific tools. Trying to check their accuracy with rulers as some have claimed to do, is not logical - The calipers would be telling you your ruler was inaccurate. Also, I doubt few people could judge by eye that the edge of the beak was in the middle of a rulers' marking to 1/2000". There should be NO free play in the depth gauge, or anywhere for that matter. When held to the light, the edges of the jaws should appear to meet perfectly with no light. The same should be true for the beak on the other side, used for measuring internal diameters. Mine were perfect out of the box in these respects. In fact, mine are broadly equivalent to my $200 6" Mitutoyo digital calipers - Which don't have fractional inches, as they are older. They are not quite as smooth as the Mitutoyo, but after the use they have had, they are not far off being that smooth now. Where there might be a difference is in (fairly esoteric things for most users) things like the co-efficient of expansion for the stainless steel they are made from? In warmer weather, the metal expands and affects their accuracy. This is why micrometers are held in the crook of one finger, to minimise heat transfer, as these are typically an order of magnitude more accurate than calipers. Most micrometers measure to 1/10,000", but only for a 2" diameter. I find it incredible that digital calipers can maintain 1/10 of that accuracy, but to much greater widths. Now I do know that temperature co-eff for my Mitutoyo, but I could not find one for the Vinca (only that the accuracy was taken at the standard 20 degrees centigrade.) I wonder if Vinca could respond with an actual figure, or is it not known / varies from batch to batch?
Kris