My first experience with a red dot sight was a BSA that I bought for around $30. It really wouldn’t hold a zero, and the dot completely washed out in bright sun. It was okay for indoor pistol ranges, if you could co-witness it with iron sights. Outdoors, or without iron sights, it was a headache.
Although I’ve had a few bad experiences with Tasco/BSA optics, I bought a PDP2 for Ruger Mk.II based on a handful of good reviews. That one worked out well, so I bought two more.
The one that I’ve used the most is mounted on a Glock 17 race gun. Despite being pelted with brass enough that some of the finish has worn off the bottom, is still holds a zero pretty well, as long as the mount and ring screws are kept torqued.
The dot is medium sized at 5MOA. Reasonably good for accuracy, and for speed. A bigger dot would be better for action shooting, but it’s still faster than trying to line up the front sight, rear sight, and target. An 8MOA dot would be better for action shooting.
Brightness settings are good on this scope. I’ve used it in dark indoor pistol ranges, and outside in bright sunlight, without any problems. I had a little trouble with the dot fading away at random times. I accidentally pulled the spring out of the battery compartment cap trying to stretch it out. It still works, and I haven’t had the dot disappear since.
The sight uses 2 357-type batteries, commonly used in lasers and digital calipers. The batteries are available in Wal-Mart stores in 3-packs at a reasonable price, as well as in most drug stores. Although I haven’t kept track of battery life, they will last a dozen or so hours, at least.
With the included sunshade screwed in, the scope can be mounted with a single wide ring, like an Aimpoint. As an added benefit, the sunshade helps keep powder fouling, thrown up and back, off of the objective lens, when mounted on a compensated or ported pistol.