ASIO4All is a WDM wrapper. It makes WDM drivers appear as asio to the host program. It also makes it difficult for you to multitrack if you intend to record more than 1 stereo track at a time. A4All also adds 11 ms delay to your signal but it doesn't report it.
MME drivers are a holdback from Win95. The latency in those is in the area of hundreds of milliseconds. Not the drivers you want to use for tracking.
Some cards work better using WDM, others prefer ASIO; most soundcards have both drivers. Some software hosts work better with one driver; Cubase works very well using asio while Sonar, in my case, uses asio because it works better with my particular soundcard. With my previous SBLive, I used kxdrivers because of better performance, but it couldn't sidestep the audio flaws of the card. In my experience, I've found asio to be more responsive; it's only a matter of finding the sweet spot for one's needs.