I am coming back from a hiking trip and this thread showed up in my view, so couldn’t help but post this here:
I have the Windrider 3400, and I absolutely love it. Bought it about 9 months ago - by far the best trail backpack I have ever bought. Very lightweight, very durable, very comfortable, very fashionable. Kind of in love with dyneema now (originally designed for catamaran sails, but turns out it makes a great ultralight backpacking fabric as well).
Probably not great for carrying synthesizers though.