I have mostly Mastercraft Maximum (Canadian Tire house brand) and Tekton impacts, but also a few Kobalt and Sunex to fill in some gaps / missing sockets. So figured I'd take a few pictures for comparison to try and see what these "features" are that people are talking about.
First picture shows Mastercraft - Kobalt - Sunex - Tekton left to right, the Sunex and Tekton are 3/8" drive and the other two are 1/2" drive. All have laser etched sizes on them. I have also oriented them for the picture squared up to their drives, so how they sit on a socket rail. Note that the Tekton and Kobalt sockets the size etching is pretty much perfectly straight on. I can attest the whole Tekton set has all of the etching and size markings perfectly centered around the drive so all the sizes are pointing out on the rail. The Kobalt has a small amount of variation, but nothing gross.
I also only have a few of those so can't come to a solid conclusion.
The Mastercraft is a little off-center but still very visible. Throughout the sets the etching 'walks' off-center here and there, but none are horrible. I can see them all on the rail, the etching is large, and even with significant use only a couple are worn to a point that it makes it more difficult to read.
The Sunex is the most disappointing by far. The laser etching is way off-center from the drive end and the size is almost illegible on a socket rail. The etching is also microscopic compared to the other three brands. Not impressed at all.
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On the plus side, the Sunex is the only one of the four that has the sizing stamped on it. Again though, like the laser etching, it's very small. I'm not sure why the sizing has to be so small on them - you have to think it's not that much more effort to make them a normal size. I'm also still young-ish and have decent eyes, and I feel like half the people I know over 50 would need reading glasses to see these markings.
Kobalt has some kind of product number stamped into it but not the size, which seems like kind of a waste as well. If you're already stamping numbers you'd think they could have added a couple more digits. The processing is already there.
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Looking next at the business end of the sockets, all four have off-corner engagement as a "standard feature". All four have tapers to help guide the socket onto the bolt head. The Sunex has an advantage here in thickness as it's noticeably a bit thinner, and the Mastercraft is noticeably a bit thicker.
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Finally, the drive ends - and sorry for the picture being flipped. Now the Mastercraft is on the right and Tekton on the left. You can see three of the four look very similar. They have a tapered lead-in to the drive, and off-corner engagement. The Mastercraft is getting a bit wallowed, but it has also been much more heavily used.
The Sunex is the biggest disappointment with no lead-in / taper whatsoever. In fact, the edges of the drive are kind of rough and raised, like the machining process to make the hole was done from the inside-out, and left raised edges around the drive that weren't ground smooth or cleaned up. This is the only Sunex impact socket I have currently, but I can say it's a real PITA to get onto the anvil in comparison with all the others. The lack of taper and raised edges require you to put the gun pointing up on a table or in between your legs and you to visually line it up to install. It also has the hardest corners of all the drives, so little relief in terms of binding on the corners during install.
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Also of note, all four have pin release holes. The Tekton is marked CR-V, the Sunex is marked CR-MO, and the other two are unmarked, but I assume they are CR-V by the looks of them. People can argue the supposed merits of CR-MO but the difference in material between them is pretty negligible to me, and like I said in an earlier post, I've never broken one from any of these brands.
Not included in the pictures, but both the Mastercraft and Tekton are tapered on the smallest sizes. I don't have any Sunex that would require it, but from pictures it looks like they are necked down.
So I'm curious to hear from some of the Sunex fans, like Yarpo, why they think they are such good value? I bought this single 21mm 3/8" drive Sunex to give them a try since everyone seems to talk so positively about them, but so far I don't see it. The drive end is so crude it almost looks home made. The etching is so far off-center I can't even read it in my tray, and both the etching and stamping is microscopic. The only positive I can give them is they are thinner, but that's never been a big concern for me with impacts. I can't say I can ever remember trying to stick one of those fat Mastercraft sockets into a hole that was slightly too small to the point the Sunex would have fit. And the tapered sockets are such small sizes I don't know if I've ever used them more than a couple times. And if clearance on a particular bolt is such an issue, I'd probably just slap a chrome socket on it and cross my fingers.
Overall I'm happiest with the Tekton's out of the group I think, although the Mastercraft's have been great and don't owe me anything at this point. Tekton were the least expensive, the laser etching is dead on every one, and they have a nice blend of having OK size and all the 'normal' features like off-corner engagement and lead-ins at both ends.