Aston Shell is probably the best replacement shell, followed by Stardock's stuff.
Their biggest problem is lack of standardization. As a result not all the skins work with every system which leads to either crash prone or outright system failures, most of which is related to the fancier graphical stuff, which suggests that they need to reexamine their memory usage coding and enact a minimum standard.
The biggest problem facing general computing today is not specifically hardware or software related, it's lack of standardization in newer arenas. Example, DVD burners have to be built to burn to every media imaginable, where CD burners have one standard. The reason Windows became as successful(and like it or not, Windows is the single most successful software product ever) as it is, is because it provided a standard for other companies to build to and that consumers can rely on. Remember how it used to be in the old days? You not only had to worry whether you had the right hardware for your nice new spreadsheet program but that you had the right OS enviroment also.
Whoa...kinda went on a tear there for a minute...sorry, that's how my mind works.
