So I should wait a couple of years before being able to use my "supported" soundcard, right? dammmn now I *have* to test ALSA again
Most of the common soundcards just work (every single thing I have ever plugged to any of my computers for example). The bit more exotic ones like the one you have have varying level of support (because the vendors themselves don't necessarily publish drivers and even if they do it might take some time; otherwise implementing the drivers rely on the community which then again depends a lot on the hardware they have). However Xonar DX should be fully supported in ALSA. It's always possible that the driver reports false timing information and then PulseAudio doesn't work properly. Such issues should be reported so someone might actually fix them. In any case fixing bugs in ALSA driver beats implementing support for thousands of chips in OSSv4 (not to mention all the other features).