Over several models companies touted things like double the processor speed. That seems to have plateaued for all save Octicon who was playing catch-up. The rocketing improvements in the last 10 years or so made more elaborate software/claims possible.
AFAIK, the recent couple of cycles haven’t had the “double the speed” claims so they moved toward software tweaks. Those get blown out of proportion by their PR department.
Put that all together and you get product that sound and act slightly different. But there is a difference and a client may like one over the other. That’s a choice that is there for each of us. It is ok to like the approach of one over the other but we shouldn’t blow things out of proportion.
Pick out an aid that sounds and works well for you. The only way is to try them. Don’t have buyer’s remorse over the claims you run across in advertising or thread here. Often, best is the one the fitter has worked with the most because their regular use improves their skill with the software.
This may tell you something. My well qualified ENT has gone through 3 brands and 3 audiologist in the 8 years or so I have used him. It is a big practice and pressure from Costco, Buyhear, et al has him looking for better results. Evidently most brands are interchangeable to his informed view. He’s concentrating on the economics and quality of the fitter.