Viscose is a type of rayon. In my opinion, it is a spectacularly poor choice for upholstery. It will tend, over time, to mat down and water spots (think spit and urine) extremely easily.

Fabrics will have a "rub test" that indicates the number of cycles of rubbing before appreciable wear. I've seen fabrics rated from 10,000 to 400,000.

Fabrics will also have a "cleaning code."
W - water based cleaners (this is what you need for most food and body fluid stains)
S - solvent based ("dry cleaning") only There are few places that do this and S-cleaning does not remove most soiling and stains.
WS or SW - use either
X - vacuum only

While claiming a fabric is S-code is a cruel joke on cleaning people (most are OK with a careful water cleaning), there are 20% where it is serious.

Aesthetics aside, I find microfiber very easy to clean and keep good looking.

Here is a link that might be useful: Chenille cleaning

blends are the way to go.
Rayon, polyester and cotton.

The new microfibers collect lint and look cheap.

I'm thrilled with the quality & durability of Crypton fabrics. I recently did very large L-shape window seat cushions, wedge pillows, & dining room chairs in one of their fabrics (Velese, which I'm not sure they're making now. Very velvety; soft, with a wonderful hand.) I got samples and mistreated them every way I could and they never showed anything. If you can provide your own fabric I'd certainly investigate these. Their faux-suedes are wonderful. The manufacturer sells yardage, but other retailers discount it a great deal. Good luck!

Here is a link that might be useful: Crypton