Disappointed you didn't rate Same engines. Powerstar engine is good but nothing more. Hard on fuel, prone to drop a valve and fuel issues, prone to blow by. I think you're being sentimental.These are my two choices also. The Powerstar was such a massive improvement on the old engines that it was almost unbelievable. They moved CNH larger tractor engine of Ford design into the very top tier and they run for ever almost with very few issues. The electronically controlled injector pumps on a couple of models played up though.
The Cummins was a simple design built of fewer parts than most and just worked very well indeed. A cheaply built engine in construction efficiency terms that just worked well by any measure you care to use. Torquey, fuel efficient, long lived, simple to service and repair/overhaul and reliable. A better engine than all rivals apart from the Powestar.
Perkins generally had good engines and almost defined the ‘average’ by which others were compared to. With that in mind they are good engines with few exceptions but lost their way and then lost the majority of their customers under Cat ownership for various geopolitical reasons.