Disney's Magical Express service doesn't really differ among resorts.
DME has been very very successful and has a lot of fans (like me). Roughly 5 million people have used DME so far. From what we read on the DISboards, there are incredibly few negative experiences, and an overwhelming majority of positive experiences. Truly, the "negatives" we read aren't actual negative experiences, but rather are either anxieties about the unknown from people who are concerned about trying it for the first time, or are the result of unrealistic expectations (people mistakenly thinking DME provided services that it doesn't provide).
So I love DME, as do many others, but it's not for everybody ....
DME is a shared ride on a motorcoach, and it's free. A car service gives you private, personalized service, for roughly $120 or so. They'll both tend to get you to your resort in about the same amount of time.
Both work just fine ... choose on the level of service you want and how much you are willing to pay for it.