My experience using the Siltarp is as a gear awning…
Design: three-season solo tarp
Ease of Setup: Done in 5 or so minutes depending on campsite.
Weight: .5 lbs
Price Paid: $75
My experience using the Siltarp is as a gear awning during climbing class outings, a rain shelter for a beach trip, and as my primary shelter for a 4 day stint on the PCT.
Setting up a tarp requires a bit of ingenuity and creative thinking as before you get to a campsite while thruhiking, you're never completely sure what variables (trees, rocks, ground hardness, etc) you may have to deal with. Given these difficulties, I've found this tarp to be very good at what it does.
It's 1/2 lbs and takes up almost no space in your pack. There are billions of ways you could use it or set it up (emergency rain poncho, quick warp-around shelter, windbreak, pack raincover), and for a solo hiker, there are few good reasons to leave it home.
The only consideration is that the width is short enough that one must take a guess where bad weather might come from overnight, and stake THAT side to the ground. Staking BOTH long sides to the ground results in something very hard to get into (though do-able if weather turns snarky).
As for use as a day shelter, these worries fade somewhat - no difficulties here.
The Siltarp takes some consideration to use, but presents a size and weight and flexibility of use that make it a no-brainer in my pack for solo ventures.