Although it was years ago we used Mears, I'm agreeing with "mrFDNY" about the long ride and multiple stops when using Mears. Simply put, I'd rather dish out an extra Grant and have a calm, quick ride than to go through Mear's cattle car ride again.
I'm curious though, isn't Disney's ME partnered with Mears? I Love Disney... Hate Mears... if this is the case, I'm not sure I'd trust ME to get my vacation off to a magical start, or end.