I was kinda hesitated to buy this sling pack, but I finally bought it since my waist pack was always getting wet when I fly fishing.
I didn't have the chance to test the DWR material in the first 2 fishing trips. But, I finally tested it out in a straight 5 hours cold and wind downpour and the content was completely dry. The working "bench" is just about right. It makes changing flies easier and it stops me from dropping flies into the water. I could bring 2 2-sided fly box, an extra reel, lunch, power bar, leaders and tippet. The D anchor allows me to carry a spare fly rod in it's tube. Enough extra anchors for you to rig your tippet holder and to carry your net if you must.
I suggest Patagonia to add into this sling is a sheath for forceps.
And another suggestion is to train the sales reps or the store owners on how to demonstrate the sling. Those guys swung the sling wrong from above their right shoulder instead from underneath their left arm.
A great product, I even put my daughter's diaper, wipes, snacks, drinks, camera and wife's pursue into it for a trip to the Zoo.