You can see the other reviews about accuracy. I found it within tolerance (0.3 deg) for 90 and 45, the two I checked against metal angles.

PROS:
- The tight/loose knobe works well for me and I can set it to the tightness that suits my use.
- The rulers have tight edges and they kind of "bite" into wood (I'm using redwood), so it doesn't slip around like my non-digital metal protractor.
- The length of the rulers is good for my work to get a good angle measure while being a reasonable size to fit in my drawer.

CONS:
- It turns on if you breath on it. I end up popping the batter out a little until it won't turn on. The battery holder is pretty tight in there, so it doesn't slip further out on its own. It's easy to do. As a side benefit, it avoids draining the battery :)
- The ZERO button is right next to the tightening knob and the on/off. It's too easy to hit accidentally. It should be recessed or something to avoid accidental zeroing.

I wish I had bought this years ago. I've been a hobby woodworker for about 5 years; making some furniture, but mostly military flag and shadow boxes. On occasion, my mitered corners were less than perfect and all I had were combo squares and the big orange speed squares to help me out. The result was sometimes great miters and other times I needed twice as much wood filler as I should have needed.

Fast forward to this handy tool. I wanted to bisect a 45 degree angle and knew 22.5 was the answer, but since my miter saw won't cut that, I needed to get close on the band saw and finish on the 12 in stationary disc sander. The angle finder locks into place, letting me get close with the band saw and sand to perfection. You can find/recreate angles as well as verify the setup of your saw and other shop tools

I also used it to validate the 90 and 45 of my plastic speed squares. Turns out one that I've had for years was not 45, so whenever I used that for projects, I was sure to have sub optimal results.

As the senior-most sheet metal fabricaor and ME for a billion dollar company with a large sheet metal department I was forced to re-evaluate our protractor needs after a bout of faulty protractors from a traditional manufacuter. I decided to start looking around. Having tried every digi and manual on the market; This was the winner.
It's not perfect by any means, but it hands down beats any other model I've experimented with.
Pros: Digital readout means fast aquisition of angle. Accurate sensor as I could ever need. It reads to 1/10s degrees and it means it. No parallax error in readout = no need to do the one eye squint. Large radius lead edge means you can use it to measure interior angles of work pieces up to .68" interior radius
Cons: the battery tray does have a very good positive lock and tends to displace itself with use. Also the + prong doesn't have a very good design for solid contact. The battery will likely outlive the contacts. That is just sad, but it's better than an $80 manual with a missed weld and a miscalibrated indicator mark out the box.

Other thoughs: I chopped the lead blade down to the 3" mark and reamed the hole on the other end to make it easy to hang. Wish that was a standard design option

I run a 20 foot press brake for a living. That is, everything I do is all about the angles. I've had all sorts of different protractors over the years, from Sterrett to Mitutoyo and five or six others. My good protractor is a Sterrett cast iron job from a combination square set I bought for a couple hundred bucks. I use both the tri-square, and the protractor every hour of every day.

But this thing, cheap as it is, blows them out of the water like a nuclear torpedo.

Seriously, this has cut in half or more the amount of time I spend checking angles. It's accuracy is decent (certainly within the 1/2 degree shop tolerance we have) and it is extremely easy to use. The digital readout is easy to read, which is a blessing for my poor worn out eyes. (I can barely read my old Sterritt without reading glasses, which I can't wear while running my machine. So I was constantly switching glasses. Yeah, I have bifocal safety glasses, but they're a pain to use when running my machine.)

But there are some down sides. Down sides I will happily live with.

First, this thing is very cheaply made. In my environment I don't expect it to out-last the batteries. This is okay. For the price and the amount of time I save using it, I'll just buy another one! but it is a downside.

Second, the battery is prone to falling out. Unlike some other devices, you can't easily tape the battery compartment closed either. But oh well. It doesn't fall ALL the way out, just enough where it shuts off. Push the tray in and all is well.

Third, it doesn't remember it's zero after it self-shuts off. No big deal, but if you leave it sit at a particular angle over lunch when you come back it will have set that angle to zero. Easy enough to fix, but a mild irritation.

All these irritants aside, this is a great product for the price. It works wonders. The only reason I don't give it five stars is for the three above reasons, and I almost did anyway.

If someone would make pretty much exactly this, but with a little sturdier blades and a higher quality mechanism, I'd marry it.

(Note: I work in a heavy industrial job shop, the majority of the time bending 3/8 to 1/2 plate. I also bend up to 1.25 plate, and down to 11ga on occasion. All of it up to 20 feet long. When you need to go down a length of 3/16 plate 20 feet long and check for angle consistency, this has been the best solution I've ever had. Bar none.)

Simple, precise and fast. I like the locking action on the hinge, a short twist locks it snug. The zero/tare function is simple and intuitive, using positive and negative angles. It can also be 'zero'd' to odd acute/obtuse angles, eliminating the math involved. Inexpensive and reliable so far. I've tested against my truest squares and it's been on the nuts each time.

FYI, the corners are sharp. I filed mine down with no issues.