Mine is a newer one, the original platen, work rest and tool arm are both cast. I've heard a few people comment that the old ones seemed better than the new ones, but my experiences differ. Of the several older Square Wheels I've seen and used, they all felt flimsy compared to mine. The side cover and top deflector were made of much thinner material, and little things like the switches seemed cheaper. I didn't notice much of a difference in how they felt when they ran, however.
I've done a number of additions and modifications to mine that make it usable. The removal and replacement of the drive wheel with a smaller 'slow-down' wheel was #1, and completely necessary. Most likely I should have spent the money on a variable speed setup.
Another modification I did was removing the separating material on the tool arm:
This allows me to compensate for the smaller drive wheel (as now there's more slack in the belt to take up because of the reduced circumference), and it allows for
just enough room to use a 12" wheel:
It's funny, looking at this picture it occurs to me that I never use the work rest I made for the big wheel... I just freehand everything, and for whatever reason I make fewer screwups without it!
If had to do it all over again, I'd spend the long dollar and buy a 2hp variable speed Bader BIII. The grinder is the machine that does the most for me, and the one I enjoy using the most, too... nothing wrong with driving a Chevy, but if you could drive a Bugatti, wouldn't you?