While looking for some crimping tool I've come up to this post.
Oh yeah, I also promised updates on the TZ-4228B.
I can happily report that it works great on JST PH (2.0mm), JST SM (the 2.5mm wire-to-wire connectors with flat pins that are commonly used on LED strips), and JST VH (3.96mm).
It does not work particularly well for Molex KK 3.96mm, as those contacts have diagonal/offset insulation crimps (just like Dupont) that demand a round insulation die. The small 2.54mm Molex KK discussed in prior posts have symmetrical insulation crimps that work perfectly in this tool.
So the upshot is that so far, the TZ-4228B is proving to be very versatile. The crimps aren't quite as good as OEM tools would create, but they are still good, and at 1/20th the cost, this is a totally acceptable compromise for hobby use.
I'll also add the observation that the sweet spot for wire size seems to be around 24-22AWG (~0.2mm2-0.35mm2) for the majority of the contacts. This tool's dies simply aren't designed for super thin or super thick wires. Going just from memory, I would suggest that the 4 jaws work best for:
1 (JST PH, XH): 26-24AWG (0.12-0.2mm2)
2 (JST XH, SM; Molex KK254): 24-20AWG (0.2-0.5mm2)
3 (JST VH): 24-18AWG (0.2-0.75mm2)
4 (Dupont): 24-20AWG (0.2-0.5mm2)
In any case the contact needs to be sized to the wire. All the real manufacturers have different size contacts for different wire sizes, but the Ali/eBay vendors often mix and match, and don't tell you which you're getting. For the most part, it seems that the female Dupont contacts are the ones for thin wire, while the male ones (and gold-plated female ones) are the contacts for thicker wire, which I prefer.
I mostly "crimp" spade connectors and JST PH and XH for my DIY projects.
Until now I basically used pliers and a point of solder. It worked fine for my needs but I wanted something better.

After reading the thred I've got the 4228B and the SN-48B.
And here the issues are showing... now I want to say that I'm a complete noob on crimping,
as said before I've used plers until today.

SN-48: the die is lose, the lower handle is shaking in the lever pins, like if the pins are too long.
Shaking it it makes rattling sound. Something is moving inside one of the handle mold.
I'm not sure If I have to notify the seller that it has probably damaged in shipping...
I've crimped some spade connector I had around and it worked fine. It was quite easy compared to my method.
I did 4 connectors in a row!

Then due to my success I've moved to the to the JST PH....
according to the post I should use the first position of the 4228B.
I've watched and watched again my tool but I cannot find a way to identify on which side the connector goes.
While the bottom die is different in the two section the top one instead seems (to my eye) the same for both section.
So no difference for the insulator crimp and the copper crimp.

Well I have a lot of connectors so I decided to go with try and error...
I did 7 or 8 and none really crimped the wire, only the insulator but only on thicker wires.
I've tried different way to position the metal piece. I've noticed that I have to do 2 separate crimp If I don't want to mangle the part that goes into the plastic housing
I have to do the two steps otherwise the part get smashed.
But even doing so the second one still have no effect on the wiring wings...

Is the tool/die defective or its just me?
Its hard to take a decent picture, but you can see that the wire is not crimped and, that the metal insert is not complelty compressed.

Should I ask for a refund?
EDIT: Ive tried HX too, and also in this case the wings that should crimp the metal parts are not folded.

EDIT 2: I've found something similar to my issue:
https://ae01.alicdn.com/kf/Ab9dbaa7560e340bea85b5f38307838b0T.jpg