The salsco roller has a dual drive system that provides much better traction that the Toro machine. Even if the rollers do slip, the smooth steel rollers cause a lot less damage than the single vulcanized rubber traction drum on the Toro machine.
The weight of the two machines is actually a bit deceiving. According to the specs, the Toro machine outweighs the Salsco by almost 90 lbs. (I'm talking the standard Salsco Roller, not the Roll and Go). However, the Salsco has a heavier PSI across the rollers (4.2 vs 3.75), which is why it performs better for aeration purposes. The Roll and Go is even more of a difference at 10.2 PSI, though I personally think it's a bit too heavy and I've seen creasing occur if the greens are soft or wet.
The other downside to Toro machine is that the traction drum is only 30" long while the total rolling width is 47". That makes for a weird weight distribution that in my mind would result in a less consistent putting surface.
Hope that helps