The Canson/Epson Baryta, and the Canson/Epson Platines are the 4 papers I print on most often (~80% of the time, between them), and honestly, going back and visually examining prints I can't tell at all which ones were made on The Epson versions compared to Canson for each paper type. I lean towards the Canson because A) I can usually find it cheaper * B) There are more sizes available C) Stock at the store is usually better D) The Epson is newer and I'm less sure about its long term consistency.
At the moment I'm equally happy to print on either one.
MS
* Epson sometimes has buy-2-get-1 mail in rebates, which is the main reason I stocked up on some of the Legacy papers.