I love RAAM's Shadow, because I definitely wanted a taste of a fight ON E-Day.
Now in my opinion, I think a lot of people like RS a lot because it had that Gears 1 feel. The return of the Berserker, the feeling of being on foot in a warzone filled city, and in my opinion Minh and RAAM helped transition the the experience to Gears of War 1.
But saying that, I liked the regular campaign and the DLC equally. Both gave me this fulfilling story that I enjoyed and will eventually replay both again and again.
The only thing that bugged me about RAAM's Shadow is the Gears 2-3 enemies. It's a nit pick I know and of course it has a real world explanation (not invented yet) but still. Just my perspective. Also, why did Jace have a different voice actor? I didn't think he was that young compared to the Jace in Gears 3. Lol, just weird that Jace now has three different voice actors.