I'm an Internet service installer and I go through hundreds of these plugs. I've found only one or two out of maybe a thousand with defects (like missing contacts). They are every bit as good as the ones the big boys sell for an order of magnitude more money. This is my go-to plug for shielded work.
I've not had one bad connection or crimp or loose fitment with these. I use a simple crimp tool, (old and worn) with no issues. Multiple purchases between March and June, maybe I've been lucky with good batches?
PROS: Good fit, solid connection on both solid and stranded so I don't have to carry both types. With the metallic jacket, these stand out so that I can tell if I or one of my guys installed or re-crimped the cable.
CONS: None so far. I've been through a couple hundred already and will order more.
I could not get a make a good cable with these heads. I tried multiple types of cat 5,5e, krimpers and still the cannot get a cable to pass on my tester. Also the cable sheath pinch breaks off every single time no matter what i do.
CONS: Inconsistent quality and failed to get one good cable out of twenty tries
Compared to the cost of other shielded connectors, these do a fine job.
It would be nice if the plug's metal shield had a little crimpable tab that the braided drain wire could be fastened into, rather than hoping the it gets clamped between the cable jacket and the plug shield I'm sure that would increase the price, though maybe still less than the competition.
PROS: I've had no issues when using my regular crimper on these plugs. So far no problems with the cables I've made up using them.
CONS: They can be a little touchy to insert into the jack (need to align them carefully), but that's been my experience with other brands of shielded plugs as well.
PROS: The outer metal shell appears to hold up a little better than the plastic ones.
CONS: I ran into an issue where the connectors would not lock into place after installing on the cat 6 cable. I used the monoprice crimping tool and it places an extra compression on the connector. You have to manually bend back out the plastic tab on top, then it will lock into place.