budget table brain buster

I own a Project (Pro-ject) 2 tt (not the Project 2 Perspective), and am considering an upgrade to a Music Hall MMF-5. Not that I don't think the 2 offers great value, it's just that the plinth feels a bit lightweight to me, and reviews for the 5 seemed to indicate it would be a real step up. Or at least that's what I thought, until I started comparing the two closely. The arms are identical, the subplatter identical, and the differences between feet negligible. I can't tell whether they use the same motor or not, suspect they do. Both provide outstanding value, according to reviews. So what's the difference? The MMF-5 has a double plinth, which presumably provides better isolation than the 2's single plinth design. It also has a glass platter, whereas the 2 has a considerably heavier glass and alloy sandwich platter. Generally speaking, I think the heavier the platter the better, and I've read that some people do not like the sound of glass platters...so I'd tend to give the nod to the 2 on that score. But is the 2's glass/alloy platter superior to the 5's glass platter or is that just my stomach talking? And if the 2's platter is better, would any superiority in that department offset the advantage of the 5's double plinth? The supplied cartridges are irrelevant, as I will be using a Benz MC. The 5 is a current model selling for $629 new at audioadvisor, the 2 is no longer made, and sold for $521. More info on the Project 2 at hi-fiworld.co.uk/hfw/featureshtml/turntableroundup.html and at audiotools.com/oldlp_z.html. My other components consist of a Sonic Frontiers SFL-1 tube pre, Myryad ss power amp, some fairly schmancy cables, and Usher X-929 speakers. However, with a new enfant on board and not a whole lot of vinyl, I don't want to drop a bomb on a table. One of these budget models must suffice. Opinions welcome! (and btw, there's no music hall dealer in my area or I would compare the two directly!)