Kentmere FPVC (both matte and glossy) are the only thing I've used since Agfa's demise. The price is excellent indeed. Mostly a matter of marketing, no? Why should there be more to it?
OTOH: I have a pack of the 'new' Adox MCC coming. While Kentmere is very nice, it still doesn't get to old Agfa levels (muddiers shadows, not as nice tonality). Kentmere is excellent for playing around without getting the shakes every time you grab a sheet; Agfa (and I suppose Ilford, but I never tried that) is for those negatives/prints you want to get the last single drop out of.
I'm very curious after the new Adox. I fully expect it to 'blow away' Kentmere. Not that Kentmere is bad, just that Agfa was such a great product.
This is excellent vs excellent-plus, or something like that. Prices reflect that, with some marketing tactics thrown in on top.