I have Arc 20W with V72 battery from Voltaic Systems. Works great, even in the shade (I decided to get it when watching a video on youtube where the owner said it works in shade). It's a great gadget. You will be hard pressed to find a power bank which will charge with 1.1A it outputs, be their batteries are great and compatible. I don't have the new V88 but I bet it's even better.

Like chrisx said, you will likely need to charge it for the whole day but the panel is foldable and you can easily attach it to a curved bike pack, your backpack or whatever. They even have backpacks with mounted panels but cycling for long periods of time with a backpack is no good.