I chose the Russian, similar but from research I've done Not a clone, designed by an individual in Russia, produced in Germany. I paid a little more but I love the Russian, I like the sealed ring on fill hole. Dont need a needle tip bottle to fill, I even prefer the drip tip, I Dont get fluid build up etc.
I prefer having a visual tank, although it comes w a stainless tank.
Most come w a drip tip adapter if you want to interchange them, I Dont.
There those are my reasons for choosing a Russian 91%. No leaks no fuss no muss, unless you are dumb and forget to use your lock ring and it heats up and then it will a bit through the airhole my dumb move.
I weighed it out between the two and will be buying a back up Russian even.