Quality of Sony SACD players as CD transports

To those who've used high quality redbook CD transports:

What do you think of the Sony SACD players as redbook transports going into an external DAC? I am thinking about the SCD-1, XA777ES and DVP-9000SE models.

Are these units, used for their digital out, in the same league as $3000-4000 transports like, say, the Levinson 37?

Thanks for the comments.
When I got the Sony SCD-1 as an SACD player, I was using a Levinson 37 transport, which I still think was a great piece of equipment, for CD playback into a dCS Purcell upconverter and Elgar DAC. After the SCD-1 broke in (300 hours) I compared them side by side into the Purcell, using the same type of digital cable (NBS Monitor 0), the Sony using the RCA version, the Levinson the balanced. I was so impressed by the Sony as a transport that I sold the Levinson. The guy who bought it raved about how good it sounded in his system, and I had always agreed with him until I heard the Sony. I know there are people on Audiogon who disagree with this very same comparison, and I'm sure will tell you so, but I heard what I heard, and I wasn't alone when I made the judgment. Although Sony is no longer using the SCD-1's transport mechanism, Accuphase and Classe, both of which are intended as no-compromise designs, are still using it.
I've had a variety of DACs but I can't imagine adding one to my Sony XA777ES for Redbook playback. It's that good.
I would just buy the scd-1 while you still can and enjoy it. It is outstanding for both redbook and sacd.
I have the SCD-1 and thought that I needed an external DAC. I purchased the Musical Fidelity A3-24. To tell you the truth, there was not an audible difference. The SCD-1 is great for redbook.
I have used several different Sony players as transports with excellent results. Currently the XA-777ES is is my system, but I previously had a Dan Wright modified SCD-333ES. I think either could compete with dedicated transports costing far more. I view the Sony SACD players as excellent transports with SACD playback as a bonus. The XA-777ES with the Chord DAC 64 is a big step up from the Sony's redbook playback alone, although the XA-777ES is an excellent redbook CD player. I'd only get an SCD-1 if you have to have extremely slow track access and inferior DACs in comparison to the XA-777ES.