Back at the start of Fifa 18 i packed an untradeable Boateng and Varane and i was using them 'till now so i'm going to compare Rio to these two.
After doing the Schmeichel SBC -i did it the 2nd day it came out, no reviews yet- i realized i traded my Neuer to a bronze keeper in disguise as a prime Icon... But he had it's worth as i traded him in without a flinch to Rio's sbc. Best decision. Ever.
Let's get the cons out the way first then, shall we?
Balance(57) and vision(57). Not major cons, to be honest, nothing serious at all, it's just some times if Rio collides with someone when running back or forward, he may fall over with his low balance (not when lets say, he fights for the ball, but when he is off the ball, running to his position). The second "con" is his vision. Yes he has good shortpassing(83) but his vision is poor so i advice you to pass back to your keeper or other defenders near him or just kick it up the field.
Okay, so let's see the pros.
Defending(91). All of his def. stats are above 90. I can't say anything bad about it, it's perfect. Can't be better! Standing tackle, sliding tackle, interceptions, heading, he wins everything! I did not use any better CBs in this game yet.
Physicality(86). Nothing to fault here either, especially as i use anchor chem style on him and all of his stats are above 90. He is aggressive, strong and can jump. He is already a steel tower in the middle, and when he jumps he pushes the earth down not himself up...
Third pro is his speed. For a defender (with anchor chem) to have 94 acceleration and 87 sprint speed is like giving wings to a tiger. Damn he's fast! He catches up to Ronaldos (both), Jesus', Sons, Hazards, Aubameyangs, etc. With med-med workrates, he never goes out of position so he easily catches anyone and when running back from lets say a failed corner attempt, he will get back and possibly stop a dangerous counter attack!
The last pro is his composure(93). He does not panic in hot situations, you could hear him shout "Mans not hot". With the complete defender, tackler and tactician traits this makes him a perfect defender to have, and these traits what makes him better then is lower rated icon cards imo! Oh and yeah, 83 stamina. He can go trough 120 minutes without a problem.
All in All
If you have untradable prime Schmeichel or other icons you don't really like, then do him. I was hesitating between him or Roberto Carlos, but a defender role is more important then a wingback so i did Rio even if i am Real Madrid fan and loved Roberto Carlos back in the day.
I do not regret my decision. I traded my Varane in while doing the SBC and placed Rio next to Boateng. Since then i do not fear any opposition through the year anymore, be it TOTY, TOTS or prime Icons. Let them come and let them be smashed to the brick wall like eggs, that is the Rio and Boateng pair in the backline.