I took my tarp insert on its maiden voyage last weekend in Grand Canyon. At just over .5 lbs, it was lightweight, compact and bugproof. I'll definitely be using it in the future, but have a few notes.
* It greatly cuts down on the usable lateral "indoor" space. The tarp alone feels huge for one person (which I love), but the insert makes it feel much smaller. The length is still generous (I'm 5'9" / 1.75m).
* The setup isn't quite as easy as the insert on my Ultamid 4. Getting the toggles into the (back, away from the door) corners took some finagling, and I would definitely practice a bit in the front-country in case you need to put it up in a hurry.
* I use 120cm fixed-length trekking poles because they are super light and pack down small. They work well for the tarp alone, but weren't quite tall enough for the insert, so it sagged a bit. The supplied tent jack wasn't as effective in lengthening my poles as I had hoped, so I would encourage using longer or adjustable poles.
* I was very appreciative of the pocket to store my glasses in the middle of the night.
* I am interested to add a guy-line to the top and use this without the tarp in the future.
I hope this helps other people considering making the purchase!