If Digi says not to use the Sis chipset then don't use it. There has also been problems with the firewire controller chip on some Sagers that limits compatibility on some firewire soundcards.
Yes, Midi/Audio may be trivial to modern PC's.........but only if you are running the correct specs for the hardware you are using. On a desktop is't not too much of a problem because you can always switch out the Mobo or use a PCI firewire card. However, on a notebook, it's essential to investigate everything to make sure your musical equipment will work.
Otherwise, you will get reduced track counts, popping/clicking with track playback, undue processor overhead, Vsti problems, and so on.
I pesonally am waiting on the new Sager to check out it's specs and I am going to choose my hardware accordingly. If I can't find anything, I'll have to move on to another solution.
If music making is casual and fun, most any notebook will do. If you make a living from music(like me
) choosing the correct equipment is essential. It will stop many headaches and problems down the road.
Hope this helps.