I'm from Brazil and this was my first video game system.
As far as I understand Nintendo didn't really have a legal patent of the system internationally at the time, so Gradiente got away with releasing a clone. I'm not sure about that though.
What I am sure about though is:
The games Crime Busters and Ghost Busters came as pack in for my system. These were, as far as I know, actually licensed from their developers.
Namco released some games also, that were manufactured by Gradiente. Those were black cartriges with a round top. I got Pac Man and Rolling Thunder like that.
Latter the NES was licensed and these black different cartriges seem to have disappeared. I got some original NES (imported) cartridges latter that worked just fine, and a couple Famicom bootleg cartridges that worked just fine with a passive pin adapter. I am not sure though wether my system was modded in any way. The system came with two controllers and the lightgun, and a couple years after I got my SNES I gave away the Phantom System with all games. It was still working flawlessly. I think I was lucky to get that. to me the console design is nicer than the front loader, and I prefer the genesis controllers to NES originals.
To be honest I don't know how good the clone was. I never ran into a game that didn't run, but I didn't really compare graphics with other systems. I am not sure wether maybe colors were off, or glitches happened.
I read somewhere that Gradiente was preparing to release the Atari 7200 in Brazil, but then came the crash, the NES was released and releasing a 7200 in that landscape wasn't gonna stick. So they got the tooling they already had and made this NES clone, which explains why they used the Atari 7200 as the shell of the console. Why the sega stuff though? Not sure. Maybe they actually got their hands on moulds for brazilian SEGA products? These could even have come out of factories that were producing actual licensed SEGA products in Manaus, like nowadays we see happen in China. That's pure speculation though.
To me the Phantom System is the coolest ever NES. MAybe because it's what I grew up with. But I don't think so. I think it's because that Frankenstein monster is actually pretty damned cool.
Now I live in Germany, so I won't even try to get my hands on one of these. But I remember clearly the first time I played that system. And it's funny how in the beginning I didn't even know what an NES was. I got that Phantom System with it's games, and I didn't even realyze it was a clone until a couple years latter.
That's all I remember now, but I'd gladly answer questions if I can.