Most would say the Frigidaire Frigidaire spin tube dishwahers are not particularly good, however if loaded correctly, I have found them to be just fine. Of course I still haven't convinced myself to install my turquoise 58 in the kitchen in St-Liboire.... lol
Admittedly, I only have the single-wash model. I bet the dual-wash Imperial does a decent job!
PhilR has a 63 Imperial as the daily driver in his all-Frigdaire mid-century kitchen - it does a fine job for him, however he's had issues with leaky pump seals - this appears to be the Achilles Heel of this dishwashers.