My primary complaint with this tool is in Klein's advertising of this crimper, which I've seen in many places including Orka, Amazon, Klein, and other retailers and distributors: if you're just scanning the description you can leave with the impression that this tool can crimp non-pass thru RJ-45 connectors. It may crimp some according to some reviews, but it doesn't crimp all of them.
My secondary complaint with this tool is that there doesn't seem to be a good way of locking the ratcheting mechanism closed. I found you can do it by twisting the override just the right amount (I know, unhelpful) but all it takes is the touch of a hair to release so it clearly wasn't designed for this.
My tertiary complaint is the cost of the pass-thru RJ-45 connectors, which is only relevant to the tool because the tool is designed to use only them. For my purposes (low volume) it's fine, but the world should have learned from Sony that designing a proprietary technology and then designing other products to rely on said technology is a recipe for failure. I won't be happy when Klein ultimately discontinues the pass-thru connector line, effectively rendering this tool worthless. This product should have been designed in such a way to allow crimping of standard non-pass-thru connectors.
In my opinion, the primary and tertiary complaints are superficial because while I initially felt misled, I did ultimately understand the pass-thru connector requirement and researched the cost before ordering the tool, and proceeded to order the tool anyway. Therefore, I'm only taking off one star for the lack of ratcheting lock design flaw.