The issue I see between the APO's and the vintage scopes is the focal length. The FCT-100 has a foal length of 640mm compared to 1500mm with the Unitron. I can use longer eyepieces for a more comfortable viewing experience with the classic vs the APO. For wide fields, the FCT-100 is great, but I have to Barlow it or use really short fl eyepieces for high mag viewing.
Please don't make the assumption that an apochromat is automatically *always* short focus, just because it can be, because it isn't.
Thomas, very true. Most would consider an f8 longer focus and slow. The FS-152 is f8 with a focal length of 1218mm. It is a very long tube, and though light at 25lbs, requires a hefty mount to really enjoy. For modern APO's, f8 or longer are rare. The FC-100 at f10 is a good example. The 4" Nikon would be another.