How long is longterm? My Spoon's about a year old, so a few thousand miles on and off road, it's gone a wee bit shiny but it still works perfectly. My Knife's newer, maybe 500 miles but a few decent crashes, it's rashed up but it's held together and again, still works perfectly. If I kill either, I'll get another the same, they're very good.
The Knife's not a comfort saddle. That is, it's not uncomfortable but it's not comfortable either, you just need to be the right shape for it. I am, and it suits me perfectly but some people find them uncomfortable due to the lack of shaping and the very thin padding. Spoon suits more bottoms I reckon.