I ike Semi Slav better
Slav Defense Vs GruenfelD??

The slav, I would say is much better than the Grunfeld. This is mainlytrue for lower rated players. The slav is very solid and reliable. You can get roled playing the Grunfeld if you don't know theory.

Slav (without dxc4): Kinda solid, black plays naturally and plays to neutralise the white initiative. Stronger players might have some problems outplaying weaker players, but of course it's very possible to win.
Slav (with dxc4): Kinda complicated, everything can happen, the first player to make a mistake loses, except if the opponents conuter-blunder (common), the best player has excellent chances to win, but fair chances to lose.
Grunfeld: Complicated, theoretical and theoretically black is equal. Gives both sharp counter-attacking chances and asymmetric endgames. The best player has excellent chances to win, but good chances to lose against a well-prepared or stronger opponent. Excellent if you like playing against the centre, probably the worst choice if you love to have space.

The Slav is almost certainly a better practical choice of opening than the Grunfeld for most players. It is sharp, but can be played schematically.
The Grunfeld requires Black to learn how to play many different types of positions, all giving Black a slightly inferior position with best play. The amount of work required to learn the Grunfeld renders it almost unplayable for non-professionals.
If you play correspondence chess, the Grunfeld may be even better than the Slav. It is very difficult to defeat the Grunfeld in correspondence time controls because Black can look up the best defenses to white's numerous attacking choices.
From a theoretical perspective, both openings are good. From a practical perspective, the Slav is a much more sane choice of opening repertoire even for those who seek maximum points as Black in OTB chess.

You can probably play the slower Qc7 stuff in the Grunfeld exchange and try to outplay White. I wouldn't touch it otherwise honestly.
i prefer SLav against QG!