I'm a backpack junky.
I love them and I have way too many of them.
The last great purchase was the SABLE RUCKSACK - OLIVE from JustPorter for $200. I love it until I got my SpingBag in Orange.
Main Points:
LIGHTWEIGHT!!!! it's super ultralight, compared to the Sable which is 500grams heavier.
Ultra-Comfortable: This is a big point. Some of the ransack that I tried before they were ok as the shape of the backpack, but the SpinBag it's amazing. I just love how much I can carry and feel that it's hugging me.

I will write a full review in my website https://fmillan.com/spinbag

I am so happy that I picked the 30L bag (was first considering the smaller bag). I think it is a really versatile yet really stylish bag and so I use it everyday for everything between flying to business meetings, day- and weekend trips, commuting to work (by bike), bringing gym gear for after work workout and more...

I've used it every day since I got it and still no real signs of wear and tear, this bag will be with me for a long time - a big thanks for a great product to the team at IAMRUNBOX!

I purchased both size bags and found them far more durable than any product. Years of traveling checked at airports, hiking, bike touring!!! After almost a year and a serious bicycle accident I had a small hole where most materials would she'd against the pavement. I patched it with a tough reflective sticker and it's as good as new. All I know is that it's the only back packs I'll ever need, recommend and ever purchase again.

Bag is spacious: fits all I need for gym (a towel, and sportswear including shoes). It has nice set of compartments. I am satisfied with the quality and the looks of it. The only downside is that the center of mass of the bag is quite far from my back which makes it move a bit more than I would like. Otherwise - great so far.

Best back no jiggle jaggle no rubbing it just clings to back brilliant

They have really done their homework well - this is a great running backpack!

I have tried several professional backpacks both for bicycling and running to work. I frequently have to carry my laptop back and forth and always a change of clothes, and a 10 k run with a backpack that is moving around a lot is simply too uncomfortable. Having just received my new Backpack Pro 2.0 I have run 40 k in 7 days, first with just a simple change of clothes but the last runs with a laptop as well. Works beautifully and so much more "stuck" to my back. Can't say anything about longevity yet of course, but if it holds up it is definitely a winner and good running companion.