Both are very good rifles. I have 5 Sako's in various models and a Cooper 52 Excalibur.
I bought the Cooper based on reviews etc and while it's OK I prefer the Sako's.
Just curious why you prefer the Sako's?
To me the Sako action is smoother, the trigger is narrower and fits and feels better in my finger, the Sako's I have shoot as good or better than my Cooper and they were cheaper.
The Cooper is a very good rifle but I'm not sure I'd spend the $$ on another new one.