They belong to completely different genres, so "better" depends entirely on what you enjoy.
| Preference | Pick |
|---|---|
| Story, humor, "aha!" moments | Portal 2 |
| Freedom, creativity, mastery, multiplayer | Skate 3 |
| Relaxed, finite experience | Portal 2 |
| Long-term hobby, community content | Skate 3 |
Both are classics. Portal 2 is a tighter artistic statement; Skate 3 is a platform for player expression.