As stated on the label, the tubing is custom, butted CrMo. Custom means it was drawn to SBI's specifications and consequently does does correpsond directly to any of the manufactuer's tubesets. The manufacturer is likely Tange or Ishiwata.

A relatively modern, butted tubest would generally be considered better than your older, plain gauge Vitus set. It will certainly be lighter, but the ride characteristics have more to do with design and construction than the materials. The bicycle will almost certainly respond quicker to both steering and pedal inputs. It will probabaly also ride a bit harsher, with bumps being more noticeable. Whether or not you like the ride quality will only be known after you try it. Often, it is quite easy to adapt to a different ride, so I suggest that you not dismiss it after one ride, but live with it for a while. Based on the description and price, you should easily recoup your costs, should you not like it.