Well, first off the DACs that inside of the better DVD-A players are often every bit as good as the ones used in the better CD players. Also, if you playback your CDs using a digital link, then it doesn't matter one bit how well the DVD player handles CD audio since in that configuration it only functions as a transport.

In the past, it has been less expensive to buy separate SACD and DVD-A players. That's largely because the first batch of universal players had to build entirely separate playback circuit assemblies with different sets of DACs and processors for the SACD and DVD-A formats. It was like having two separate players under the cover. Then some less expensive universal players from the likes of Pioneer and Toshiba came along that cost under $200. Those were cheaper because they converted the DSD signal from SACDs into a PCM format (which is what DVD-As and CDs use).

Now, you're starting to see DACs that are capable of handling both the PCM and DSD signals in their native format. Denon has put out a few players with this design, and other players are following suit. The main thing to watch out for with the universal players is with the bass management. You need to make sure that the crossover applies to both formats. Some universal players would implement the bass management for the DVD-A, but not with SACD playback.

The main impediment to buying two players is that most receivers/processors can only handle one multichannel analog input.