This is Marths best Neutral stage, hands down. There are so many positives to the stage for Marth users. First off there are the platforms. The top platform is at the perfect range so you can dolphin slash safely. Even if you miss, you will land on the platform with little lag. The side platforms allow utilt and ftilt to hit opponents above you. Ftilt pressure under a platform is very potent. Note that you can still tip a Fsmash through the side platforms. Its just a lot harder in Brawl, possibly character dependant as well. If an opponent air dodges, you can go underneath a platform and occasionally sneak in a upsmash.
The point is, Marth's combination of decent air speed and fast aerials make platforms extremely helpful.
The platforms also hurt projectile camping and allows alternate approach methods. In example, you can use the platforms to keep yourself unpredictable. What I tend to do is jump on a platform, drop down, double jump up and nair. Platforms also help against Dedede, ROB, and Diddy Kong. Simply because platforms will usually hurt their game as it helps Marths.
The ledges on the stage are dolphin slash friendly. Unlike Final Destination, you cant get gimped by the ledge. The ledge design will sort of "suck you in" like a twister when you get close to it. It seems VERY easy to recover on this stage. If you tip an aerial, it will likely be a KO because the stage boundaries are real narrow. The easier it is to recover, the more chance you have of gimping. Easier gimping = win.
Otherwise, this is Marths best neutral. The only character that I can think of that will not mind at all is Metaghey....sigh.