My regulator finally arrived today, several days late due to UPS "re-routing" it to somewhere in CA... At any rate, It looks to be solidly constructed and maybe worth the $50+ price. As advertised, the downstream gage read 45 PSI when I installed it, and the pressure adjustment was a straightforward flathead screw with directional arrows to eliminate any guess work. Only time will tell if the unit remains functional and leak-free, though it will be in constant use for the next several months, and I have until 31 January to return it to Amazon. I assigned 4 stars, because it arrived intact, looks good, and works as advertised out of the box; however, I believe the price was a little high, judging by the material/technology, and the fact that it was made in China (like EVERYTHING else I've purchased the last several years). I will be sure to submit a follow-up review if anything changes to warrant a revised review.

Only used it a few times so far, but works as it should

I purchased this awhile back, I have used this multiple times with outstanding results.
This is manufactured with a liquid filled gauge, that is not water filling the gauge from use as mentioned in some reviews. Gauges tend to be precision instruments it will handle a bit of use and handling but not much, or constant abuse. This instrument is well made and works as designed. There is no reason for constant or repeated adjustment. Before putting it in service, flush it for 10-20 seconds, turn off supply close off service side with a plug, a valve or even a kinked hose, set your desired pressure, and enjoy the peace of mind you get from knowing your equipment is protected from excessive pressure which is the purpose of this gauge. I rarely find products that I give five stars too. Shipping was timely, product is well made, works as intended, price was reasonable, user friendly, no bells and whistles added that detract from its intended purpose or ease of use. Checks all boxes for five star rating. Being as I'm an ornery old cuss I look for reasons to take away star ratings... I'm disappointed. I could and would recommend this product to a friend without hesitation.
Update...
This has been in service for more than a year, as I have given it a five star (grr)can't change star numbers, it is holding up to reasonable handling. It's held the 40 psi setting since its original setting. I was recently hooked up very high water pressure, at check in they even highly recommended a pressure regulator. I flush my filters and hoses prior to hook up, it was by far the most pressure I've ever encountered, the regulator held my preset pressure spot on

My previous one got frozen, so I got a new one. These have better flow than the fixed output regulators, but are easily damaged by freeze. I use the fixed one in the winter months and this one in the summer. This one has better flow and can be adjusted higher in pressure which probably helps with the flow.

We have tried various kinds of water regulators or restrictors as they are known as. I even got one with a gauge on it, but of course I did not know exactly how much pressure I was getting. The park we are now in has about 120 psi and would have burst our pipes, and all the regulators I had, 2 of them said 50 psi but that was not a true number. We got this one and turned on the water and with a screwdriver and about 1 minute adjusted the pressure to 50, a real number, and voila, I now have plenty of pressure in my kitchen faucet, after a year and a half of trickles. The shower and the bathrooms were ok but not the kitchen. Even my new faucet works better, I thought the sprayer was broken because it wouldn't stay on, the problem was the pressure, no problem now. This is the best regulator, so easy, screw it on and use a screwdriver in very small increments, I am so glad I got it and am sorry I waited till now. I recommend it highly. The only reason I didn't give 5 stars was I am only using it 1 month and want to see how it lasts. I will not ever forget to take this with us when we leave. Worth the extra money.