Never heard of Marian, but you are aware that PCI is going the way of the Dodo, right? Also... seriously? An ADAT interface from this century that still doesn't support S/MUX for higher sampling rates? That should just require some pretty basic driver code.... And no 64-bit support, and no Windows 7 support.... IMO, you're setting yourself up for a very expensive lesson if you buy this product....
Regarding the other one, as a general rule, anything by Creative is designed for gaming, not recording. You should just plain avoid everything they sell. And, of course, as you noted, it won't solve your problem anyway.
I think you'll be a lot happier if you buy a product that was actually designed for recording and has decent support from a major manufacturer. There are plenty of companies with established reputations in this area, but the two companies you've mentioned so far aren't on that list. You might get lucky and find a diamond in the rough, but it's a crapshoot. I'd look for products (preferably external USB or FireWire products) by better manufacturers.
I tend to group manufacturers into quality tiers, ranging from consistently exceptional down to usually usable.
The intent is that only companies that almost always make solid products make it into the top tier.
The second tier is a combination of products whose quality is more variable (some cheap junk and some good stuff) and companies that are lesser known (whose reputation hasn't been thoroughly established yet).
The third tier is companies whose products are known to be not-so-great, but they're cheap.
Top tier:
- Apogee
- Echo
- Edirol
- MOTU
- RME
- Tascam
Second tier:
- Focusrite (I debated whether this should be first or second tier)
- M-Audio
- Mackie
- Phonic (too new to the digital space to have much of a rep yet)
- Presonus
Third tier:
Hint: search for an "audio interface", not a "sound card" or "ADAT card".
It's better to spend a little more and get something that will work well. Spend less, buy twice. The bottom end for usable ADAT-capable hardware is probably about $350. It's usually only provided on higher end hardware because most people are using it to add an extra eight inputs to an interface that already has lots of inputs.
You might be better off selling the Behringer and buying an audio interface sufficient to handle your needs rather than trying to find a way to build a system around ADAT.