"Once you go deluxe, it's hard to go back."
Sounds like a snobby statement to me.
It would be different if the WDW Deluxes were truly deluxe. It's not like they are the 4 Seasons or the Ritz. They simply get the name "Deluxe" based on location and a couple amenities, and ridiculous room rates.
I've stayed at the Poly a number of times, if I had my choice right now I'd choose CSR over the Poly every time. I just decided I like it better.
The phrase, "Once you go deluxe, it's hard to go back", should be tempered with a HEAVY grain of salt. I would in no way suggest to anyone that this would be true for them.
I've stayed at Poly, CR, WL, AKL, Golf Resort, Disney Inn, Shades of Green, CBR, CSR, OKW, FW Cabins, DTD Hilton, and my last short trip was my first time trying a value, POP. My trip to the POP was as enjoyable as every other one listed above.