Hi Quintin,
I'm in the Los Angeles area but I thought I should offer up my recent experience as you are in the same spot I was about 2 years ago. I print on an Epson 3800 and 9800 and produce fine art editions for several artists showing in museums and galleries around the world. I started trying various paper samples looking for an OBA-free alternative to the Photo Rag, as it does state in the specs that it has some. And of course I also wanted a lower price. I settled on the MOAB Entrada Rag Natural. I've used both the 290 and the 300 gsm, depending on the availability and price. Occasionally I find the double-sided 300 on sale and it ends up costing less than the single-sided 290, but not often. I only need single-sided anyhow.
In the past 2 years, I've used the Entrada Natural paper almost exclusively. I really love this paper and so do my clients. I print mostly warm-tone black and white images, but have also used the Entrada to produce some gorgeous color prints from old Kodachromes. I have experienced very little (negligable) amounts of the dust spots mentioned in another post. No more so than with any other matte surface fine art paper. I usually spot them with a Conte charcoal pencil.
For my comparisons I printed the same images on Entrada and Photo Rag and found the blacks to be a bit richer on the Entrada. This is printing through Photoshop and using profiles provided by the manufacturers. I sometimes use Colorburst RIP with other papers and tried the Colorburst profile for Entrada but wasn't happy with it. The profile provided by MOAB was so good that I haven't bothered to try adjusting the CB profile. Of the OBA-free papers, MOAB Entrada has been the closest in base tone and surface quality that I can find to Photo Rag and I feel the image reproduces better on Entrada. The Photo Rag base appears just a tiny bit brighter, perhaps because of OBA's present? I'm not sure as it's just from my observation, not through any measurement.
Hope this helps in your search and that MOAB paper is available where you are at a reasonable price should you choose to use it. Happy printing!
Althea