Was in the MP Beta, so I don't know about SP...
But MP is fun, if you can deal with rushers.
Wacky units (APC with a big cannon, can shoot infantry over obstacles and such. Already kinda weird, but if you've got bear infantry too it becomes utterly hilarious, moving into your enemies base and dropping bears all over the place xD ), nice graphics, especially the water effects, everything else is the usual.
If you like C&C you'll like RA3

One thing that bugged me however, although it was the last Beta stage, some units seemed kinda unbalanced, dunno if they worked on it afterwards.