It has a similarly light and fluffy fiber, and a similar softness, but it doesn’t irritate a lot of people who find mohair irritating. Most importantly, the suri alpaca also comes in a lace weight, which means you can hold it double with other yarns and achieve the same gauge as or a very similar gauge to what you would achieve when holding the base yarn double with a lace-weight silk-mohair blend.
Silk mohair is a little finer, and the fibers have a more wiry texture to them. Its undyed, natural color is a little on the yellower side. Because of the silk, it also has a slight sheen that catches the light. The suri alpaca has a hazier look to it so it will soften out colors more, and its fibers are a little thicker. Its undyed, natural color is less yellow than the silk mohair yarn.
The loose, fluffy fibers of the mohair catch on each other and create more stability. This allows me to knit at a looser gauge than would normally be ideal for the yarn I’m using. As a result, I can knit really light, fluffy garments that are warm but not bulky. The suri alpaca brushed fiber is not quite as stiff as the mohair. That means the fibers won’t catch on each other quite as well, so the resulting fabric won’t be quite as sturdy. It also tends to be a bit heavier than mohair, so you’ll notice a little more heft to your project.
I bought the undyed silk-mohair yarn and the undyed suri alpaca in this post from stickchick on Etsy. If you’d like to experiment with more colorful yarn, Camellia Fiber Company has a glorious suri silk lace-weight yarn, and Eden Cottage Yarns has some of my favorite silk-mohair yarn.