New to this board but had to respond to this post because I just got my order of Swish in the mail last night. This is my first experience with it so I don't know about longevity, but I knitted up a swatch last night and I love it. It's incredibly nice to knit with. I threw the swatch in the washer and dryer and it's so soft. I'm definitely going to try making something with it.
I really like the Shine too but it tends to split when you knit it up. For the price though, I'd say you can't go wrong with either yarn.
I'd be interested to hear from others who've used both more extensively how they hold up longer term.