This is one of those abiding mysteries, like the purpose of Stonehenge, or what keeps Donald J's Hair in place in a high wind...
OK, well, Mato= Matotoys. and that's the Shantou Mato Plastic Toys Co Ltd of Guangdong, China. They make a range of plastic toys and lately have cornered the market in all metal tanks, and metal upgrades.
Company info (if you're still awake

):
https://mato.en.alibaba.com
Websites:
http://www.matotoys.com/main.php
or,
http://www.matotoys.cn/eng/main.asp
Torro seems to be part of WSN/Trumpeter (a merged company) also based in Guangdong...perhaps unsurprisingly, maybe next door to Mato. and also owned by Shantou?
https://sunnykids.en.alibaba.com/company_profile.html...
http://www.matorro.com/home_35.html
However, the European distributor of High end Torro tanks (the weighty metallic ones) is based in Germany. Much as Taigen, as we know, it is based in Florida with the Imex Company. Imex imports and improves Taigen products, and even manufactures its own improved parts.Thing is, though, the high end Taigen (so-called
'Pro' and 'Metal' editions) and Torros/ Matorros, that often come in their own ammo crate style boxes, are virtually identical. It's said that Taigen is a spin off from Heng Long; a bit like a Lexus being the luxury version of a Toyota.
WSN/Trumpeter seem to be part of the same group, but specialise more in static (non-RTR) models. But here's the link to Taigen, for comparative purposes.
http://www.taigentanks.com
Hercule Poirot and Sherlock himself were invited to untangle the links between these inscrutable Chinese firms, but gave up in a cloud of pipe smoke, and opium
One thing is, they're all connected. They all share (and pinch) each others ideas, and there's no hassle about copyright or intellectual property...especially as they pinched it from Tamiya in the first place. Allegedly
'Mato' probably means something in Cantonese (like: 'Tamiya'..copy), but I don't know what. As for the qualitative differences: the more it weighs, the more you pays.. That seems to be the golden rule. Sorry for the crap rhyme.