I can't compare an X-Fi era Creative card with the Xonar, as I haven't had a Creative since the Audigy 2ZS Platinum Pro but I don't miss their poor drivers/support and I love my Xonar.
My Audigy is still in service but every wee while it forgets it's installed and I have to take it out and put it in another PCI slot to remind it. Very odd indeed! Nothing much to do with sound quality though I suppose... I do miss the break-out box of the Creative, but not much else. Xonar for me.
My audigy used to have that very same issue.. Forgetting its there and a PCI slot rotation cured it great.
Im sure that was on the Gigabyte 965P DS3, and I am also sure that I cured that issue with a BIOS update... in fact, no, thats exactly how I cured it, so... Something for you to check out there.
As for the breakout boxes, yes, I still call them Live Drives. But my speakers ( Altec Lansing 995 ) have no volume control or headphone socket, and so I am pretty much forced to use some for of Drive bay for the headphones and the keyboards need a volume control too.
I prefer it this way anyway.
But the Live Drive issue can I suppose be cured with Front I/O Panels however none of them give me the stuff that I get on the creative bays.
I recently bought the ASUS thingy fron OCUK and it was utter rubbish and I got a refund ( minus postage ) and in the end I bought the Fatal1ty... Thats a total waste of money if you ask me.
My main PC and my kids PCs all have Creative cards with teh Live Drives.
My No2 PC has a xonar however, but no live drive ( Doesnt need it, but I will still find somehting for it cos thats how I like my PCs )
Plus I just like the front end to look "Busy". I hate bare systems they bore me.
Last year I was considering changing my X-FI extreme music for a Xonar, cos I had upgraded from pc speakers to a av amp and bookshelfs,
Go for it.
The better your AMP / Speaker setup, the better you will see the Xonar is.
Although to be completely honest, the XFI has a very wide range on its EQ settings and that crystaliser is a bit funky. They are a lot closer than many people seem to make out, but the xonar definitely is better.