It's better than average but not for the money.  My vintage CDP sounds better via Coax than the PWT via I2S.  So would the Marantz or Cambridge Audio.  I gave one a spin for few weeks when I had a  new production PWD mk2 in for diagnosis.  I would not drop that kind of dosh on a PWT.  I'd rather look for a sd card reader than could output I2S over the PWT, if one exists.  Off ramp is the better way to go than the PWT.

The Oppo is a mediocre digital transport at best.  I had a 103 which is the same except for the analog output stage.  It was outclassed by current Marantz and Cambridge Audio offerings, not to mention vintage players that were even better.

In fact, I found the Bluray playback surprisingly unspectacular as well.  Nothing special about the Oppos IME.

A friend of mine has an old Sony XA series but impressions seem to indicate a lack of low end performance.  I'll have to give it a listen one of these days.

What constitutes vintage when you're talking SACD players? Do the older Sony, Marantz, Denon units count?

The XA5400ES was real hot shit for awhile, totally FOTM. It was alright, nothing spectacular. You often see a bunch of older Esoterics floating around on Audiogon for less than $2K, usually DV50s. Don't bother. They look like their big brothers but that's about as close as it gets. Entry level Esoterics have never been anything to write home about. Same with the Ayre CX-7, despite Stereophile slobbering all over it.

For redbook transports you probably can't go wrong with Sonic Frontiers. Parts Connexion can service and upgrade them. Simaudio transports are usually pretty good. You can also often find a Cary 303/300 for under $2K. Definitely not a bad player, but I would plan on sending one to Cary to be checked out, I know some of them had laser problems. Same with the Plinius. The Gamut CD-1 on the other hand was just crap and should be avoided.

Hmmm...don't the Accuphase SACD transports be considered as such? Admittedly their HS-Link protocol is proprietary but digital nevertheless?

A few companies have developed proprietary links allowing for SACD transport/DAC combos. That's always been allowed, provided the link is impossible to extract the data stream from. What you can't do is output DSD via S/Pdif or AES.

Hmmm...don't the Accuphase SACD transports be considered as such? Admittedly their HS-Link protocol is proprietary but digital nevertheless?

Yes, that's why I said 'their own compatible', same thing as proprietary.  So what are you planning to do w/ the CAT-5 cable from the HS Link??  This is just Accuphase doing the same thing others do using HDMI.  Plus, do not confuse this HDMI output as I2S because the jacks might look the same, totally different.  Ergo, you build a proprietary system using the same manufacturer or listen to the analog output, or rip the SACD layer and make it your bitch.