I am very lucky to own one of each - an RV Metro and a wenge/tulipwood/maple burl 535 that I bought off Gwilym (see post 2 above).
Whilst both are excellent and versatile basses and there are many gigs where I'd happily use either, for me it's usually an easy decision which one to take. For me to take the MTD, I'll need to know the bass will be safe and secure and that the modern appearance would fit the bands image. However, if the venue is more rough & ready and/or the band has a more vintage-vibe (that's 95% of my gigs!), I'd take the Sadowsky for its classic vibe & replacability.
I would also add that the cheaper Grendel and K series MTD basses are excellent and worth a look if you were thinking Sadowsky Metro rather than NYC.
Hope that helps.