I really liked certain things about my Wisp...primarily the volume and comfort of the shoulder straps and waist belt. The more durable materials is appreciated as are the load lifters. However, there were a few things that really aggravated me, namely, the lack of pockets. It has a pocket in the lid but it's not big enough for my water bottles or lunch/snacks and other things I like to keep readily accessible.... and the waist belt pockets are not overly useful for anything but the smallest of items. Also, at 24 oz, the pack was heavier than I preferred.
First step was to get rid of everything I didn't need: excess strap lengths, zippered bladder pocket, foam back pad, bottom compression strap, "helmet carrying flap", rubber hydration port, and the haul & ice loops. The next step was to add side pockets with elasticized tops, a 4-way stretch mesh front pocket and crisscrossed bungee system. I also reangled the top compression strap, made new attachment points for the flap lid and made a new and lighter sternum strap that rides in a lower more comfortable position on me. Lastly was the replacement of the GG logo on the flap with the yin yang symbol...symbolic for my keen interest in Chinese philosophy.
The final weight is 18oz. The next step is to remove the waist belt pockets which I'm guessing will save another ounce.
I'm very happy with it though I am thinking I'd be willing to sacrifice some durability for lighter main body materials. Will ponder the options over the winter.
The first pic is the stock Wisp. The other two are the modified version (basketball for scale).