One is no better than the other -- they both have different purposes.
I would recommend using t-molding on the outer edges of your side panels, and melamine edging on the edges of any access doors or interior shelves (rear door, front access door etc) since t-molding would not be appropriate as it adds thickness to the edges. Think about cabinet doors -- they're always laminated on the ends, not t-molded. I used melamine edging on many parts of my cab, but always used t-molding on any outside edges where humans come into contact.
Melamine edging is also a good way to line the insides of any handle holes, routed vents or speaker openings, to give a nice finish and to keep the edges from crumbling with repeated contact. It's also much easier to apply (using only a hot iron) than t-molding, which requires cutting a slot in any surface where you want to apply it.