Its got a lot of stuff I'd love to see in a Diablo III (assuming we get one), but it also has a lot of annoyances, bugs, and imbalances.
Sacred is unapologetically a Diablo clone, which is fine by me. If you know how to play Diablo, you know how to play Sacred. Hell, if you know how to differentiate between the left and right mouse buttons, you know how to play Sacred, so its very accesible. It does a lot of stuff really well: a large seamless world full of sidequests, the ability to ride horses, and six inventive character classes (the vampiress changes as the day and night cycles change).
However, there are some major problems. For some strange reason, your avatar won't always attack when you click. I'd be stuck in positions where I was surrounded, and I'd try to attack, but my guy would just stand there, swinging in random time intervals as he lost health. Also, a glitch caused a vital quest item to not appear, forcing me to use cheat codes to continue the game.
Subsequent patches have probably solved these problems, but there are still other problems. Strangely, shopkeepers only sell about four health potions at a time, and enemies don't drop them all that often. Any Diablo fan knows that potions are a necessity. Imagine trying to get through the jungle act of Diablo II where you only have six or seven potions at a time. There are no scrolls of town portal to give you convenient access to shops, and bad guys respawn behind you, so even running back to town is hard.
If the frustrations were removed from Sacred, it would be the next best thing to Diablo II. I'd recommend Divine Divinity instead.