Thanks in large part to the PRG, I'm one of those "high volume customers" you talk about.

I'll continue to put significantly more spend on my Amex cards than any others (as in many multiples) as I see Amex as the best overall card company - and it's not even close. I get much less hassle from Amex (actually, zero hassle - they are a dream to work with compared to the rest of the bunch) - they are used to high volume - Chase, let alone the rest of the card companies, aren't.

I don't see what Chase has to offer for high volume customers that would see them move their business. Chase is closing the gap with Ink, but still trail by a long way. The rest of the Chase line up is strictly for punters.

About the only advantage I see is URs have better transfer partners than MRs - but not by a huge amount. That said, Amex offers transfer bonuses that can offset UR's advantage if you can take advantage. Overall, I'd say MRs are perhaps ~20% less valuable, but in specific instances when bonuses are available, can be ~20% more valuable.

Oh, forex fees on many Amex are indeed an irritant. But I suspect a big incremental profit center that Amex is loath to lose - but I wonder how many even notice that extra charge on their 6 figure monthly bill (much of which is reimbursed or is a business expense anyway?)