I've owned both, though I haven't had the Modulus for a while. Still, talk about an apples-and-oranges comparison!
Both have 35" scale. The Modulus has medium-narrow spacing (unless you order the new Wide option) while the MTD has full 3/4" spacing.
The Modulus I had wasn't particularly heavy, but the two MTDs I had were among the lightest basses I've owned.
The Modulus has very consistent, even, almost compressed response up and down the neck (especially with EMGs like mine had) while the MTD is very lively, responsive, and sensitive to differences in dynamics and technique.
The tone of Modulus probably varies somewhat depending on which pickups you have, but while I've heard it can be somewhat warmer with Barts, the MTD has a very woody, organic tone that's like nothing else I've played. My two MTDs also both had wenge necks, and the wood selections make a big tonal difference with MTDs, as well.
My $.02 worth--others may have different opinions and experiences, of course!
Mike