It's big, immersive and great sounding........
SS3 is the closest to this with Iwo Jima. A great map and sadly its why I bought this game. I've played every WWII rts game under the sun from COH series to Heroe's but there is something different about ss3. Since I have not played the previous title I can't rate this against them but rather against the other rts games out there based off the period. The maps are huge and the units are historical.
What ss3 does right is strategy. You can't rush into the heat of things expecting good results. No. Instead you must devise a strategy and use your units in away that spares there little lives. Ah, yes don't be wasteful now.
The graphics are adverage if not dated but the sounds more than make up for what this game lacks. Booms and explosions are all great sounding and immersive.
There are five campaign maps, Allies, Crimea (Russian), Iwo Jima (American, Japan) and Germany late in the war. The early war battles have been left out due to under powered weapons of the time but I would have liked to seen the Battle for France, Holland, Belgium, Crete, North Africa, etc in here somewhere. However, Fire Glow plans to release a free addon next month that will add more campaign maps (France included) and multiplayer support, parachute troops that can be dropped on the battle field and rideable units like tanks.
This game is no small feet. The maps or battles are huge covering square miles in real units so its easy to get overwhelmed here but if you take your time and learn the strategy it will be worth your while.