The SX-73 was Stella's club racer model. The frame is hi-tensile steel, though it should have forged dropouts with an integral hanger. It has been converted from it's original tubular wheelset to 27" clincher (and it looks like the valve stems are ready to be sheared off). You can see how the pads on the front caliper have been adjusted to their highest possible position. I can't identify the derailleurs but the levers appear to be the aluminum Hurets, so the I suspect this a late boom model with the nice Huret Challengers. However, the Stronglight 49 crankset is definitely the highlight of the bicycle.

As to the handling, it's should be more reponsive than your typical, boom era recreational tourer. You can see the head angle is steeper than the seat tube. It should be similar to a Peugeot PA10 or Gitane Interclub. A period road test stated, "a responsive machine for fast club rides, or perhaps a season or two of local racing...a fairly responsive machine without the choppy feel and stiffer ride a machine made with a little steeper head angle and shorter wheelbases produces...reponsive enough for most riders on our American roads, and as long as you don't try to use it to bash aorund the houses, turning nine corners in a one mile circuit, most of you should be quite satisfied with the machine".

At the current price it's a fair deal tending towards good. Remember it's only a hi-tensile frame, looks like it needs work and it really should be converted to tubulars or at least 700C, which in my mind offesets the Stronglight crankset and Challenger derailleurs.