I did the switch to C-41 fix last year. Here's the reason; 5 liters of Ilford Hypam, $25.99, 5 gallons C-41 fix, $36.50 Adorama's pricing.
Shipping for the Hypam is about $12.00, and for the C-41 about 33.00.
I ordered mine from my local camera shop/mini lab, they were able to give me a good price on shipping since they made it part of their regular chem order.
The plain C-41 fix (Not the RA version) is a a straight, nearly neutral PH, rapid fix. I found the recommended dilution by doing some searching in here, and then made some retained silver tests (using selenium toner) to nail down the the proper fixing time for my papers. (1 - 1 1/2 minutes). The RA fix isn't good for B&W, though I don't know the specific reasons.
I'm still using the last of my TF-5 for my film, but as soon as that's exhausted I'll be using the C-41 for everything.