Interesting concept for a thread. Or maybe I should say concepts, plural.
Ah, lower-end French-bashing? Always fun, even if not always justified.
Great-riding vs. collectible? Depends on whether you ride or collect!
Appearance vs. function? Campy NR vs. VGT-Luxe, sometimes beauty wins!

On my list of tells for a lower-end bike: brake safety levers, one-piece crank or crank with integrated chain guard, dork disk, stem shifters, plastic saddle, plastic bar tape.

The thing is though, these features don't make the bike bad and many a great-riding bike came with them. They do indicate where in the price hierarchy the manufacturer expected that bike to sell, who the expected rider might be and how it would be ridden. Sometimes the difference between a lesser model and a more expensive one isn't as great as the price would suggest. But you can start with those indicators.

Sorry, no pics at this time. Maybe later, after I've had my coffee.