Depends on condition, IMO.
I like em both, and own both currently.
I'd expect the Colt to have a better trigger (unless some one's messed it up with do-it-yourself-customizing).
If your Hi Power is an older Belgian made, and Belgian assembled, I'd have to think about it some before trading.
But the Hi Power happens to be from the years made in japan, or one of the later ones assembled in portugal, I'd trade for the gold cup if the Colt seems to be in useful condition.