To convert a VCF into a MAF, each variant must be mapped to only one of all possible gene transcripts/isoforms that it might affect. But even within a single isoform, a Missense_Mutation close enough to a Splice_Site, can be labeled as either in MAF format, but not as both. This selection of a single effect per variant, is often subjective. And that's what this project attempts to standardize. The vcf2maf and maf2maf scripts leave most of that responsibility to Ensembl's VEP, but allows you to override their "canonical" isoforms, or use a custom ExAC VCF for annotation. Though the most useful feature is the extensive support in parsing a wide range of crappy MAF-like or VCF-like formats we've seen out in the wild.
