Thanks. I see posts on other forums as recent as a year ago saying they couldn't get the eClaro to work with Linux. There's an open request on the ALSA support request board that doesn't appear to have any follow-up.
On my current Linux system, my Xonar D1 has been fine. My new motherboard doesn't have a PCI slot, so I can't reuse the D1. I'm also considering the STX II, but the eClaro seems to be a direct competitor for about $100 less. A DX and a Vali 2 is another option whose cost would be halfway between the eClaro and STX II. I like the idea of a single rotary volume control, so the DX and Vali 2 might be it.