I was lucky enough to find some Korean knockoffs of Minerva and Go-Shooter recently. They're the same molds as the 1980's/1990's ones you might have seen on sites like this one:
http://pleasesavemerobots.com/scrambledcity/skorbia/skorbypost88.html
There's a Lightfoot knockoff in the series too, but it doesn't have a Powermaster, and the colors are really off, so I passed on it.
They come kneeling in robot mode in strangely compact packaging. The packaging is actually a rip-off of another Korean toy line featuring transforming SD rescue vehicles called "Robocar Poli". The cardboard and plastic window are really thin. The toy is held onto the cardboard insert by a twisty tie. Overall, the packaging is probably the weakest part of these.
Compared to the original G1 toys, Go-Shooter has a darker blue plastic, and Minerva has a black abdomen instead of a white one. The paint and stickers are different too.
They feel very solid in robot mode. You can tell the plastic they used was high quality, and the parts fit is good as well. One thing I really like is that they retain Go-Shooter's ratcheting shoulder joints and Minerva's ratcheting knee joint--If this were a crappy Chinese knockoff, those features would definitely be absent.
Here they are decked out with all the accessories they come with. Like its predecessor, the Minerva knockoff's antenna are at a right angle compared to the original G1 toy. Go-Shooter comes with an extra shield (part of which becomes his rear bumper in vehicle mode), and Minerva comes with a very out-of-place looking sword.
Although the chest covers open up, the Headmaster gimmick does not activate any stats--It's empty beneath, except for some molded details.
Minerva's head fits on really solidly, but Go-Shooter's is a bit wobbly. Go-Shooter also has one rather loose fist on the right side, which can't hold his gun or shield very well. One other issue is that Minerva's hands are swapped. It's not very noticeable and doesn't impede the transformation, and it's an easy 30 second fix with a screwdriver.
They can switch heads like the original toys and they're even compatible with real headmasters and third-party headmasters as well.
Despite the couple faults, their robot modes are very solid.
Just like the originals, the heads turn into little armored humans who become the drivers in vehicle mode.
Here they are in vehicle mode. Minerva's light bar is removable, which is good since the original G1 toy didn't have one.
Here they are armed with their weapons.
I really like the look of Go-Shooter in vehicle mode, but Minerva is a little busy for my tastes, so I took most of the stickers off on one of mine. Now she looks a lot better in my opinion, closer to the real Minerva. Just for kicks, I tried de-stickering Go-Shooter too, but he ended up looking too plain.
Overall, I really like these. I had almost forgotten that there existed a happy medium between the cheapo crap-quality Chinese knockoffs and the stupidly expensive "KO Replica" toys. These knockoffs hit that sweet spot, being not perfect, but fairly high quality, and available at reasonable prices. Plus they don't say "Hasbro" and "Transformers" all over them, so fans won't confuse them for the real deal. I definitely recommend this set.
I am selling a few of these, so if you're interested, you can buy from my highendtfs.com store:
http://www.highendtfs.com/store/index.php
Or if you want to go through Ebay, I'm also selling them there (for a few bucks more):
http://www.ebay.com/sch/highendtfs/m.html?item=110779056246&viewitem=&_trksid=p4340.l2562
