I speak fluent Russian and Polish so...
Petr Yan comes off as a bit of a chav but it's because he was raised in a chav-ish city with crime and drugs being common. Actually, I am quite impressed that he has made it this far coming from an arguably shithole part of Russia. I will be rooting for him in the title fight.
Jan Blachowicz used to rub me the wrong way in KSW but he's gotten a lot more modest and serious about training in the UFC (probably gained perspective, he used to be a big fish in a small pond) and I find myself rooting for him often. He's developed an English sense of humor too, as evidenced by the recent trolling of Jones, haha.
Fedor used to be every Russian fan's sweetheart, so modest, so kind, so honest and frank. At some point he joined the Russian ruling political party tho and started responding with "God's will" to almost every question - both of these facts diminished my fandom. Russians still mostly root for him tho.
Aleks E. is just horrible. He's an insane, psychotic alcoholic. He's made friends with Kadyrov. He gets shitfaced a lot. Gets arrested and acts like that's a good thing. Talks mad shit all the time. Almost nobody likes him. Ugh.
Any other details you wanna know about anyone - ask me.