I wonder if these dealers who have stated that a Questar 7 performed about the level of a 5" apo actually did side-by-side tests.
Between 2017-2020 I performed side-by-side comparisons between the following:
1986 Questar 7 (BB) and Astro-Physics 130GT
Questar Astro 7 (Quartz) and TEC180 apo
Questar Astro 7 and Televue NP127 apo
Predictably, all three apo refractors destroyed the Q7 and Astro 7 on wide-field views. With the NP127, AP130GT and TEC180 putting up maximum views of over 4, 3 and 2 degrees respectively, The Q7 could manage around .8 degree FOV, while the Astro 7 with a 41mm Panoptic came in at a little over a degree FOV.
However, for planetary, lunar and DSOs it was not even close to a contest against the 5" apo's. A properly acclimated Questar 7 should and does put up more detailed views of the Moon without having to "reach" for the magnification, given the native f13 or so focal length, unlike the apo's which needed barlows to attain higher magnification. The contrast on the 7s was amazing, showing more complex filamental structure of M42 than the 5s. While globular clusters were resolved deeper in the 7s, I do like the wider framing of the globs that the 5" apo's provided.
As I expected, the Astro 7 could not keep up with the TEC180's 7.1" of unobstructed glass. However, it wasn't what I would characterize as a blowout - things were just a bit better in the 180 on planetary and lunar. Given the low contrast that DSOs have, the 7's obstruction did not handicap the views compared to the TEC180, and of course it is MUCH easier to transport a Q7 to a dark site than a 36 lb, 4 ft long refractor!
Unfortunately I did not do any direct comparisons on double stars, but I will say the apo refractors were fantastic at splitting doubles without any acclimation time. In order to cleanly split the double-double in Lyra, the Q7s had to be well acclimated. From a practical standpoint, all this means is that the apo's do better on spur-of-the-moment observing.