I previously owned both tables though not at the same time. The VPI 19jr is better made (ie more solid), and flexible. You'll have a better arm. It is a better sounding table than the MMF-5, but not much better sounding IMO. The plus for the MMF-5 is it's an easy to set up, leave it alone and just play music, vs other tables I've had which require more tweaking. The VPI isn't too bad set up wise compared to suspended tables, but is more effort than the MMF. But that's the cost of the flexibility to choose your arm, etc.
If the $'s are the same it may be worth the move. I replaced my VPI with a Heybrook TT2, which I like much better - YMMV.
If the $'s are the same it may be worth the move. I replaced my VPI with a Heybrook TT2, which I like much better - YMMV.