I love my outslayer bags. I considered the straps, but ultimately decided to go with chain. Chain will not leave me wondering if the bag will remain hanging. I will clearly see when it is time to replace the chain or swivels or caribeaners.
I believe the Outslayer straps are heavy duty velcro/hook and loop. In my experience, hook and loop breaks down easier than chain.
If you decide to go with the straps, please let us know how they hold up over time. I would be willing to migrate over to the straps if they are comparable to chain.