More of a good thing is never bad.
This game just have a huge amount of content. Weapons, special attacks, armor comes in a long range of flavors and you can customize and upgrade your avatars in an endless number of combinations. The amazing animations and special effects are awesome, and the battles are as brutal and frenetic as always.
But in essence it is basically identical to the other games. If you played them, you will know exactly what to expect. The only major difference is the story and new maps, plus a more friendly price tag than the others had at launch.
The story did not impress me at all though, I just found it annoying to wait for the cutscenes to finish. In my opinion they could have removed 90% of them and put more work into the game itself, waste of time if you ask me, with the only exception being the orc campaigns. They are just hilarious.
Bottom line, more of the same. If you are a newcomer to the series you might as well pick up the original games at a bargain bin. It will probably give you more content for less money, and you wont miss out anything new as there is basically nothing revolutionary new to see. That is not a bad thing if you like the series though.