I've been using a Frigidaire Flair, the 30-inch single-oven version, for just about 6 years now at the house in St-Liboire.  Yes, I voluntarily gave up a 21st-century smooth-top range with a self-cleaning oven, I very much enjoy cooking in the Flair.  I am not a tall person so the lower surface units are not a problem and I really like the eye-level controls.  I also really like the way the oven door swings up and over the oven cavity - for me, that means reaching into the oven is much easier than bending and lifting a pan up and out of the oven (my shaky hands are only going to get worse and trust me, the door of the GE oven in Ogden gets very well-splattered...).  I also like the way the surface units can be a 'landing pad' for a hot pan taken right out of the oven.  

There are some disadvantages, too - most notably that when the cooktop is fully extended it's just about impossible for me to reach anything from the cupoards above the Flair.  I guess this would be a reason why in ads for the Flair one rarely saw a set of cupboards above the range (and to be fair, I just muscled my Flair into the cut-out meant for a conventional 30-inch range).   Placement of a Flair in a kitchen could be problematic too - in my case, the Flair is adjacent to a corner cupboard and again, when the cooktop is fully extended,  reaching into that cupboard is not easy.  

Still, I have made this style of range work for me and full disclosure, there is a 30-inch conventional style 1964 turquoise GE range waiting in the wings should I get tired of the Flair!

They also weigh about 5000 pounds each.....

The largest reason was these were TOL products and expensive to build and buyers looking for hi-end TOL products mostly wanted the NEW self-cleaning ovens that everyone was excited about in the later 60s.

The design of Hi-Oven ranges were not adaptable to being built as a SCO due the the near impossibility of having enough insulation to allow a SCO to clean itself.

Then of course once one or two major manufactures discontinue something every other manufacturer follows suit.

John L.

So, it's heavy?  LOL  I feel your pain.  It's quite a feat maneuvering these through doors, around corners, etc.  

I've moved a couple of these over the years, never into my kitchen though.  One was in a friend's unheated garage for many years that I stripped for parts and another I'd hoped to restore (with my stash of parts) and decided to let it go.  I have a rather small kitchen and that imposing structure would have been too large visually and with the extending cooktop, too intrusive in the work space while in use.  I let that "dream" go and opted for the GE Liberator.  

All that said, they are terrific ranges.  I've used several in other's homes.   Classic Frigidaire Radiantube elements and good performing ovens with appropriate planning and bakeware.

Is very little heaver [ without base cabinet ] than a 40" FD free standing range of the same time period, these  ranges were not shipped with the base cabinet attached from the factory.

If you want the real deal in Hi-Oven ranges from the 60s the Hotpoint Hallmarks are much better ranges to own and cook on than the FDs. 

They had superior top burners, built in ventilation systems and much better wiring, even the bake and broil elements did not fail nearly as often as the FDs did.

John L.